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THE    WILEY    TECHNICAL    SERIES 

FOR 

VOCATIONAL    AND    INDUSTRIAL    SCHOOLS 

EDITED   BY 

JOSEPH    M.    JAMESON 

GIRARD   COLLEGE 


THE  WILEY  TECHNICAL  SERIES 

EDITED    BY 

JOSEPH  M.  JAMESON 


TEXT   BOOKS  IN  AGRICULTURE 

NOW  READY 

Market  Gardening.  By  ¥.  L.  Yeaw,  Manager, 
Oasis  Farm  and  Orchard  Company,  Roswell,  N.  M. 
Formerly  Professor  of  Market  Gardening,  Mas- 
sachusetts Agricultural  College,  vi  -)-120  pages, 
5  by  7.     36  ngures.     Cloth,  75  cents  net. 

Studies  of  Trees:  Their  Diseases  and  Care.  By 
J.  J.  Levison,  Department  of  Paries,  Brooklyn, 
N.  Y.  5H  by  8.  x +253  pages,  156  half-tone 
illustrations.  Cloth,  $1.60  net.  (Also  8  by  10^, 
loose  leaf.) 

Agrifiiltural  Drafting.  By  Charles  B.  Howe,  Bush- 
wick  Evening  High  School,  Borough  of  Jirooklyn, 
New  York,  N.  Y.  viii  +63  pages,  8  by  10»4.  45 
figures,  26  plates.     Cloth,  $1.25  net. 

Exercises  in  Farm  Dairying.  By  Professor  C. 
Larsen,  Department  of  Dairy  Husbandry,  South 
Dakota  State  College.  Loose  Leaf.  8  by  lOK'. 
69  Exercises.     Complete,  Paper  cover,  $1.00  net. 

Field  and  Laboratory  Studies  of  Soils.  By  Pro- 
fessor A.  G.  McCall.  Department  of  Agronomy. 
Ohio  State  University,  viii  +77  pages,  5  by  l^i. 
Cloth,  60  cents  net. 

Field  and  Laboratory  Studies  of  Crops.  By  Pro- 
fessor A.  G.  McCall,  Department  of  Agronomy, 
Ohio  State  University,  viii  +133  pages,  5  by  7; 4. 
54  figures.     Cloth,  85  cents  net. 

IN    PREPARATIOX 

Agricultural  Chemistry.     By  Professor  T.  E.  Keitt. 

Clenison  Af;ricultviral  College.      Keady  Nov.,  1910. 
Practical  Entomology  for  Schools.     By   Dkan   E. 

I).  Sander.so.v    and    Professor    Jj.  M.  Peairs,  West 

Virginia  Universitv.      (In     press,      lleadv     Oetoher, 

1910.) 


For  full  announcement  see  list  following  index. 
5000  8-1-16 


i-f4  A-f.  L^ 


Under  the  Soil  in  any  Field  is  Solid  Rock. 
Frontispiece.  (Adapted  from  Hall.) 


r 


FIELD  AND   LABOKATOR\ 


STUDIES  OF  SOILS 


A'N    ELEMENTARY    MANUAL 
FOR  STUDENTS  OF  AGRICULTURE 


BY 


A.   Q.   McCALL 

Professor  of  Agronomy,   Ohio  State   Ufiiversity 


FIRST     EDITION 

FIRST    THOUSAND 


NEW  YORK 

JOHN   WILEY   &   SONS,   Inc. 
London:   CHAPMAN    &    HALL,   Limited 

1915 


Copyright,  1915, 

BY 

A.  G.  McCALL 


THE  SCIENTIFIC  PREbS 

ROBERT   DRUMMOND  AND  COMPANY 

BROOKLYN.   N.  Y. 


SUGGESTIONS  TO  TEACHERS 


This  little  book  of  soil  experiments  has  been  prepared 
in  response  to  the  demand  for  a  brief  laboratory  and  field 
course  in  elementary  soils,  which  may  be  given  without 
the  purchase  of  expensive  equipment.  With  a  few  tools 
and  the  aid  of  the  pupils,  the  teacher  should  be  able  to 
construct  all  of  the  apparatus  necessary  for  many  of  the  ex- 
ercises. Such  cooperation  on  the  part  of  the  students  will 
stimulate  a  keener  interest  in  the  work  than  can  be  secured 
by  the  exclusive  use  of  purchased  materials.  However,  as 
funds  become  available,  it  is  advised  that  special  equip- 
ment be  purchased  and  substituted  for  the  less  satisfac- 
tory, home-made  apparatus. 

In  many  schools  apparatus  from  the  chemical  and 
botanical  laboratories  will  be  available  for  the  soil  w^ork. 
For  example,  a  good  balance  may  be  purchased  for  the 
joint  use  of  the  chemical  and  soils  laboratories,  and  the 
compound  microscope  may  serve  for  both  botany  and 
soils.  The  first  purchase  of  equipment  should  include 
the  following: 

1.  Gasoline  or  kerosene  stove  with  oven. 

2.  Balance  similar  to  the  one  shown  in  Exercise  A-7. 

3.  Soil  auger  and  spade. 

4.  Small  equipment,  such  as  sample  cans,  glass  tumblers, 

tin  cans,  wrapping  paper,  cheese  cloth  and  twine. 

355 127 


vi  SUGGESTIONS  TO  TEACHERS 

A  supply  of  clean  sand,  and  also  some  loam,  clay  and 
muck  soil  should  be  secured  in  the  fall.  This  material  should 
be  dried,  pulverized,  and  passed  through  a  sieve  with  one- 
eighth-inch  mesh,  to  remove  stones  and  sticks. 

The  exercises  are  intended  to  furnish  sufficient  material 
for  one  period  per  week  throughout  the  year  or  two  periods 
per  week  for  a  half  year.  Although  they  are  arranged  in 
logical  order,  it  is  not  necessary  that  the  exercises  should 
be  taken  up  in  the  exact  sequence  in  which  they  occur 
in  the  text.  Indeed,  it  will  be  necessary  for  the  teacher 
to  vary  the  arrangement  in  order  to  adapt  the  study  to 
the  season  and  to  the  facilities  of  the  school. 

A  small  working  library  should  form  a  part  of  the 
equipment.  For  a  study  of  soils  this  library  should  include 
several  elementary  books  on  soils,  a  collection  of  Farmers' 
Bulletins  from  the  United  States  Department  of  Agriculture 
and  the  publications  of  the  State  Experiment  Station. 

While  much  of  the  material  in  the  text  is  original,  the 
writer  has  drawn  freely  from  all  sources  for  suggestions 
and  illustrative  material.  Some  of  the  illustrations  have 
been  adapted  from  the  text-books  and  much  material  has 
been  taken  from  the  publications  of  the  Agricultural 
Extension  Department.  The  author  wishes  to  make  espe- 
cial acknowledgment  of  the  helpful  suggestions  of  former 
Superintendent  A.  B.  Graham  and  Mr.  Clark  S.  Wheeler 
of    the    Agricultural   Extension    Department    of   the   Ohio 

State  University. 

A.  G.  McCall. 

Department  of  Agronomy, 
Ohio  State  University, 
June,  1915. 


CONTENTS 


EXERCISE  PAGE 

ALA  Study  of  the  Formation  of  Soils 1 

A  2.  To  Study  the  Composition  of  Soils 4 

A  3.  To  Study  the  Groups  of  Individual  Soil  Particles 6 

A  4.  To  Compare  the  Surface  Soil  with  the  Subsoil 8 

A  5.  To  Study  the  Relative  Productiveness  of  Soil  and  Subsoil .  .  10 

A  6.  To  Study  the  Individual  Soil  Particles 12 

A  7.  To  Determine  the  Amount  of  Organic  Matter  in  Different 

Soils 14 

A  8.  To  Determine  the  Pore  Space  in  Soils 17 

A  9.  To  Determine  the  Weight  of  Soil  per  Cubic  Foot 20 

A  10.  To  Study  Soil  Granulation 22 

A  11.  To  Study  the  Effect  of  Freezing  and  Thawing  upon  Soil 

Granulation 23 

A  12.  To  Show  lliat  Some  SoUs  Can  Hold  More  Water  Than 

Others 25 

A  13.  To   Show  That   Plants   Give  Off  Moisture  through  Their 

Leaves 27 

A  14.  To  Show  the  Effect  of  Soil  Air  upon  Plant  Growth 29 

A  15.  To  Show  How  the  Temperature  of  the  Soil  is  Affected  by  the 

Slope 31 

A  16.  To  Study  the  Necessity  for  Soil  Drainage 33 

A  17.  A  Study  of  Warm  and  Cold  Soils 36 

A  18.  To  Study  the  Operation  of  Tile  Drains 38 

A  19.  A  Study  of  Soil  Temperature 40 

A  20.  To  Demonstrate  the  Movement  of  Water  in  the  Soil 42 

A  21.  To  Compare  the  Movement  of  Water  through  Different 

Soils. 44 

A  22.  To  Show  the  Effect  of  a  Loose  Surface  upon  the  Rate  at 

which  the  Rain  Will  Soak  into  the  Soil 46 

A  23.  To  Study  the  Forms  of  Soil  Moisture 48 

vii 


viii  CONTENTS 

EXERCISE  PAGE 

A  24.  To  Study  the  Capillary  Movement  of  Soil  Moisture 51 

A  25.  To   Show    the  Effect  of   Plowing   Undrr  Coarse  Material 

such  as  Manure,  Green  Cover  Crops  or  Clods 53 

A  26.  To  Show  the  Effect  of  a  Mulch  in  Preventing  the  Loss  of 

Moisture 54 

A  27.  To  Study  the  Water  Loss  from    Cultivated,  LTncultivated 

and  Mulched  Soil  Surfaces 5G 

A  28.  To  Show  the  Effect  of  Drainage  upon  Soil  Temperature. ...  59 

A  29.  To  Show  the  Influence  of  Color  upon  Soil  'I'emperature .  ...  61 

A  30.  To  Show  the  Effect  of  Lime  upon  the  Soil 63 

A  31.  To  Study  the  Need  of  the  Soil  for  Lime 66 

A  32.  To  Study  the  Adaptability  of  Soils  to  Croi)s 69 

A  33.  To  Study  the  Plow 71 

A  34.  To  Study  Plant  Roots  and  Their  Relation  to  Soil  Manage- 
ment    73 

A  35.  To  Study  the  Roots  of  Legumes 75 


J   3         " 

'  ,  '    5        o    :>  1 


FIELD  AND  LABORATORY  STUDIES  OF  SOILS 


EXERCISE    A  1.     A    STUDY    OF    THE    FORMATION    OF 

SOILS. 

Equipment:     This  exercise  is   based   upon   the   pupil's 
own  observations  rather  than  upon  laborator\^  work.     Any 


Fig.  1. — The  Kock  may  Lie  but  a  Few  Inches  below  the  Surface. 

natural  formations  in  the  neighborhood,  which  are  illus- 
trative of  soil-making  processes,  should  be  visited  by  the 
class.  Each  pupil  should  write  an  account  of  the  trip, 
including  a  discussion  of  the  questions  given  below. 


2        FIELD  AND  LABOEATORY  STUDIES  OF  SOILS 

Questions:  1.  Does  solid  rock  come  to  the  surface 
at- your  home? 

2.  Name  a  place  where  you  know  the  depth  at  which 
solid  rock  is  found. 

3.  Does  your  home  well  reach  the  rock? 

4.  At  what  depth? 

5.  Compare  the  shape  of  stones  found  in  streams  with 
that  of  crushed  stone.  How  do  you  account  for  any 
difference? 

Discussion:  Under  the  soil  in  any  field  is  solid  rock. 
Sometimes  this  rock  is  very  deep  and  again  it  may  lie 
but  a  few  inches  below  the  surface.  The  soil  also  was 
once  large  rocks.  It  was  made  fine  as  we  see  it  by  natural 
agencies  working  through  millions  of  years.  These  agencies 
are  stiil  at  work  and  ma}^  often  be  observed.  Water  fills 
the  crack  in  a  large  stone,  freezes  and  bursts  the  stone 
apart.  Exposed  ledges  of  stone  heated  during  the  day 
and  cooled  at  night  for  several  years  finally  crumble.  The 
roots  of  trees  force  themselves  between  the  layers  of  rock 
and  split  them  apart.  Every  little  stream  rolls  and  wears 
pebbles,  grinding  them  finer  and  finer,  finally  forming  soil. 

An  examination  of  almost  any  soil  shows  that  it  con- 
tains not  only  fine  rock  particles,  but  also  plant  and  animal 
remains.  This  organic  matter  may  be  found  in  the  soil  in 
all  stages  of  decay,  and  constitutes  the  most  important 
body  of  material  present  in  the  soil.  It  furnishes  nitrogen, 
which  is  an  important  plant  nutrient,  and  enables  the 
soil  to  absorb  and  retain  moisture. 


A  STUDY  OF  THE  FORMATION  OF  SOILS 


OS 


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EXERCISE    A-2.     TO    STUDY    THE    COMPOSITION    OI 

SOILS. 

Equipment:  Spade  or  soil  auger;  two  pieces  of  oil- 
cloth or  heavy  wrapping  paper  sixteen  inches  square; 
two  slender  bottles;  tablespoon. 

Method:  By  means  of  the  spade  or  soil  auger,  secure 
a  sample  each  of  a  sandy  soil  and  a  heavy  clay.  Place  a 
tablespoonful  of  each  soil  in  separate  bottles  and  fill  each 
about  two-thirds  full  with  clear  water.     Shake  each  bottle 


Sandy  Soil. 


Heavy  Clay  Soil. 


for  one  minute  and  allow  to  settle  for  five  minutes.  01)- 
serve  carefully  the  layers  in  each  bottle,  the  lai-gc  particles 
at  the  bottom  and  the  finest  material  at  the  top.  Use  the 
bottles  shown  above  to  indicate  what  you  see. 

Discussion:     Soils  are  composed  of  fine  rock  particles 


TO  STUDY  THE  COMPOSITION  OF  SOILS  5 

that  have  resulted  from  the  breaking  and  grinding  of 
large  rocks,  to  which  has  been  added  some  organic  material 
which  has  been  formed  by  the  decay  of  plant  and  animal 
remains.  All  of  the  light-colored  rock  particles  in  the 
bottles  are  quite  similar  except  as  to  size.  The  dark 
material  at  the  surface  or  floating  in  the  water  is  organic 
matter  which  may  be  removed  from  the  soil  by  burning. 
Both  classes  of  material  are  essential  to  the  growth  of 
plants,  the  rock  particles  furnishing  the  mineral  food 
elements  and  the  organic  matter  the  nitrogen.  The  organic 
matter  also  increases  the  moisture-holding  capacity  of  the 
soil. 


EXERCISE    A-3.      TO    STUDY    THE   GROUPS    OF    INDI- 
VIDUAL   SOIL   PARTICLES. 

Equipment:  Four  beakers  or  tumblers;  samples  of 
clay  and  sandy  soil. 

Method:  Make  fine  and  dry  a  small  quantity  of 
^ach  of  the  two  kinds  of  soil.  Put  three  tablespoonfuls 
of  the  clay  soil  in  one  tumbler  or  beaker,  and  a  like  amount 
of  the  sandy  soil  in  the  other.  Fill  each  one  half  full 
with  water.  Taking  the  tumblers  or  beakers  one  at  a 
time,  proceed  as  follows:  shake  genth^  for  four  minutes, 
let  stand  one  minute  and  pour  off  into  another  tumbler 
all  the  water  possible  without  losing  the  setthngs.  The 
settlings  are  the  sand.  Allow  the  water  poured  off  to 
stand  one  hour  until  a  distinct  laj^er  of  settlings  can  be 
seen  at  the  bottom.  Now  pour  off  and  discard  the  clouded 
water.  This  nmddy  water  contains  clay  so  fine  that  it  will 
not  settle.  The  material  which  has  settled  in  the  second 
glass  is  silt. 

Questions:     (1)  About  what   proportion   of  the  sandy 

soil  is  silt? 

(2)  About  what  proportion  of  the  clay  soil  is  silt? 

Discussion:  Soils  are  classified  according  to  the  fine- 
ness of  the  rock  particles  which  they  contain.  A  soil 
which  contains  a  large  proportion  of  coarse  particles  is 
called  a  sandy  soil.  One  which  contains  a  large  })ropor- 
tion  of  fine  particles  is  called  a  clay  soil.     No  soil  is  made 

6 


GROUPS  OF  INDIVIDUAL  SOIL  PARTICLES  7 

up  wholly  of  clay  or  of  sand  particles.  All  soils  contain 
a  certain  per  cent  of  each  of  these  groups  of  fine  particles. 
The  coarser  sandy  soil  drains  more  rapidly,  warms  up 
more  quickly  in  the  spring  and  is,  therefore,  better  suited 
to  early  garden  or  truck  crops.  Clay  soil  dries  out  more 
slowly,  and  for  this  reason  it  is  capable  of  furnishing  water 
to  the  crop  during  the  hot  dry  summer  months,  especially 
if  it  contains  a  large  amount  of  organic  matter. 


EXERCISE    A-4.     TO    COMPARE   THE    SURFACE    SOIL 

WITH   THE    SUBSOIL. 

Equipment:     Soil    auger    or  spade;    piece    of  oilcloth 

or     heavy     paper    sixteen     inches 
square. 

Method:  With  a  spade  dig  a 
narrow  trench  a  foot  deep.  Make 
one  side  of  the  trench  smooth  and 
note  the  line  at  the  bottom  of  plow 
depth.  Examine  a  handful  of  soil 
above  and  below  the  line  and  fill 
out  the  following  table,  comparing 
the  two: 


Color. 

Moisture. 

Firmness. 

Surface  soil . 

Subsoil 

Fig.  3. — Soil  Auger  Made 
by  Welding  a  Three-foot 
Length  of  Wrought  Iron 
Gas-pijie  onto  the  Shank 
of  a  1^-inch  Wood  Au- 
ger. Additional  lengths 
may  be  added  as  desired. 


Observe  the  line  between  the 
surface  soil  and  the  subsoil  wherever 
the  earth  has  been  cut  into,  cither 
l^y  a  stream  or  an  artificial  grade. 
There  is  usually  a  distinct  difi'erence 
in  color  between  the  surface  soil  and 
the  subsoil. 


Discussion:     If  the  soil  contained  nothing  more  than 

8 


SURFACE  SOIL  AND  SUBSOIL  9 

fine  particles  of  rock  there  would  be  little  difference  between 
the  surface  soil  and  the  subsoil.  After  the  rocks  were 
made  fine,  plants  began  to  grow  and  by  their  death  and 
decay  they  have  added  to  the  soil  the  dark-colored  material 
which  we  call  organic  matter  or  humus.  As  the  stems 
and  leaves  of  plants  fall  on  the  ground  and  decay  they 
are  worked  into  the  soil.  Thus  the  surface  soil  is  made 
to  contain  large  quantities  of  decaying  plants,  while  the 
subsoil  contains  but  little  of  this  material.  This  is  the 
chief  difference  between  the  two.  These  decaying  plants 
are  an  important  addition  to  the  soil.  They  add  nitrogen 
and  make  the  soil  capable  of  holding  more  moisture. 


EXERCISE  A-5.     TO    STUDY  THE   RELATIVE   PRODUC- 
TIVENESS   OF    SOIL    AND    SUBSOIL. 

Equipment:  Two  flower  pots  or  quart  cans;  wheat 
seed;  soil  and  subsoil  from  the  same  place. 

Method :  Fill  one  pot  with  moist  surface  soil,  the  other 
with  moist  subsoil,  and  plant  six  grains  of  wheat  in  each. 
Keep  the  pots  watered  and  compare  the  growth  of  plants 
from  time  to  time. 

Discussion:  Why  are  washed  hillsides  and  the  high 
points  in  the  fields  usually  less  productive  than  the  level 
land  and  the  lower  levels?  Steep  land  should  be  cultivated 
across  the  slopes  and  should  be  kept  covered  w^ith  some 
crop  in  order  to  prevent  the  washing  away  of  the  surface 
soil.  Deep  plowing  is  often  desirable  to  increase  the  depth 
of  the  surface  soil.  If  the  soil  has  always  been  plowed 
shallow  it  will  be  better  to  plov/  only  an  inch  or  two  deeper 
each  year  until  the  desired  depth  is  reached,  than  to  plow 
deep  the  first  year.  Why?  Observe  the  growth  of  corn 
or  wheat  in  the  "  dead  furrow  "  between  the  lands. 

While  the  plowing  up  of  the  subsoil  in  the  humid  regions 
frequently  results  in  a  decreased  productiveness,  the  soil 
and  the  deeper  layers  in  the  arid  regions  may  be  mixcnl 
without  injury.  In  these  dry  sections  good  crops  are  fr(^- 
quently  grown  where  the  top  soil  has  been  entirely  removed 
in  the  preparation  of  the  land  foi'  irrigation. 

10 


PRODUCTIVENESS  OF  SOIL  AND  SUBSOIL 


11 


J 


Fig.  4. — A  Convenient  Soil  Bin,  Mounted  upon  a  Cupboard.  The 
bins  are  filled  from  the  top,  the  soil  being  removed  from  the 
open  throat  at  the  bottom.  A  sloping  board  just  above  the 
opening  directs  the  soil  back  and  prevents  it  from  escaping 
faster  that  it  is  used. 


EXERCISE    A-6.     TO     STUDY    THE    INDIVIDUAL    SOIL 

PARTICLES. 

Equipment:  Two  tumblers;  tablespoon;  three  large 
lieakers  or  quart  cans;  samples  of  sand  and  clay  soils. 

Method:  (a)  Put  a  tablespoonful  of  sand  in  one  tumbler 
and  the  same  quantity  of  clay  in  the  other.  Fill  each  with 
water  and  after  thorough  shaking,  allow  the  soils  to  settle. 
Which  settles  the  more  rapidly? 

When  a  swift ty  flowing  stream  carrying  material  in  sus- 
pension is  checked,  which  particles  are  first  deposited? 
Find  an  example  of  the  sorting  power  of  flowing  water  in 
your  neighborhood. 

(b)  A  day  or  two  before  the  class  is  to  meet  put  three 
or  four  tablespoonfuls  of  sandy  loam  soil  in  a  beaker  or 
can  and  nearly  fill  the  vessel  with  water.  Shake  at  inter- 
vals for  one  day  and  finally  after  thorough  shaking  allow 
to  settle  one  hour  and  pour  off  into  another  beaker  (or 
can)  the  muddy  water  down  to  within  one  inch  of  the 
bottom.  Allow  to  stand  for  one  minute,  again  pour  off 
the  muddy  water  and  evaporate  each  separation  to  dry- 
ness on  a  stove.  When  dry,  examine  the  material  in 
each  can;  the  last  residue  is  sand,  the  second  is  silt,  and 
the  first  separation  is  clay.  Moisten  a  little  of  each  and 
rub  between  the  thumb  and  finger.     Which  ones  are  sticky 

and  which  fall  apart  easily? 

12 


TO  STUDY  THE  INDIVIDUAL  SOIL  PARTICLES     13 

If  a  compound  microscope  is  available,  examine  each 
separation  and  make  a  drawing  of  a  few  grains  from  each. 
Note  that  the  soil  consists  of  fine  rock  particles  and  dark 
humus  or  organic  material. 


EXERCISE    A-7.     TO    DETERMINE    THE    AMOUNT    OF 
ORGANIC    MATTER   IN    DIFFERENT    SOILS. 

Equipment:  Balance;  small  porcelain  or  tin  dishes; 
soil  samples;  gas  burner  or  alcohol  stove. 

Method:  Place  a  teaspoonful  of  fine  dry  soil  in  a 
dish.     Put  the  dish  on  the  left-hand   pan  of  the  balance 


Wick 

niass  or  Metal  Tube 

Cork 


Fig.  5. — Small  Alcohol  Stove  Made  from  an  Ink  Bottle  or  Oil  Can. 


and  add  weights  to  balance  it.  Now  heat  the  sample  over 
the  flame  until  all  the  organic  matter  has  been  consumed. 
Take  care  that  the  same  weights  are  on  the  right-hand 
pun  of  the  balances  and  return  the  dish  containing  the  soil 
to  the  left-hand  pan. 

How  does  this  weight  of  the  sample  compaie  with  its 
previous  weight?  How  do  you  account  for  this  difference? 
Add  dry  leaves  or  cut  straw  until  the  pans  are  again  in 
balance.     What  does  this  added  material  represent? 

Discussion:     Soils  vary  greatly  in  the  amount  of  or- 

14 


ORGANIC  MATTER  IN  DIFFERENT  SOILS  15 


Fig.  6. — Two  Types  of  Alcohol  Stoves,  which  may  be  Made  to  Take 

the  Place  of  Gas  Burners. 


Fig,  7. — A  Good  Balance  Costing  about  112.00. 


16     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

ganic  matter  which  they  contain.  Muck  soils  are  composed 
almost  entirely  of  organic  matter,  while  some  sandy 
soils  contain  comparatively  little  dead  plant  and  animal 
remains.  Whenever  the  supply  of  organic  matter  in  a 
soil  is  low  the  crop  yields  are  small.  Applying  manure 
and  plowing  under  clover  are  good  ways  of  increasing  the 
amount  of  organic  matter  in  the  soil. 

Note. — A  very  good  balance  can  be  purchased  for  about  $12.00. 
Small  dishes  should  be  about  two  or  three  inches  in  diameter.  If 
tin,  they  must  be  without  soldered  seams. 

Gas  or  alcohol  stoves  may  be  purchased  at  a  small  cost,  or  a  very 
good  alcohol  lamp  may  be  constructed  in  the  laboratory  without 
cost,  by  following  the  diagram  shown  on  page  14. 


EXERCISE.     A-8. 


TO    DETERMINE   THE   PORE  SPACE 
IN    SOILS. 


Equipment:  Dry  samples  of  sandy  soil  and  clay  soil; 
graduated  bottle  or  cylinder;  a  quart  can  or  milk  bottle. 

Method:  (1)  Fill  the  can  or  bottle  to  within  one-half 
inch  of  the  top  with  the  dry  sand  and  compact  by  tapping 


.  clc.i 
ii5'c.; 

i  -=^100| 

j   -^HIM 
(50S-    : 

|?50=-    ji 
950-g-   : 


JJl 


Fig.  8. — A  Graduated  Bottle  or  Cylinder  is  a  Necessary  Part  of  the 

Laboratory  Equipment. 

the  can  lightly  on  the  desk  top  three  times;  (2)  fill  the 
graduated  bottle  or  cylinder  to  the  top  mark  with  water; 
(3)  carefully  pour  the  water  from  the  graduated  vessel  onto 
the  top  of  the  soil  in  the  can  and  continue  to  do  so  until 
the  water  stands  level  with  the  top  of  the  sand;    (4)  record 

17 


18     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

the  amount  of  water  used.     This  represents  the  amount 
of  water  necessary  to  fill  all  of  the  open  space  in  the  sand. 
Repeat  the  above  operations,  using  the  sample  of  clay  soil. 
Report  3'our  observations  in  the  following  table: 


Cu.  Centimeters 
of  Soil  Used. 

Cu.  Centimeters 
of  Water  Used. 

Per  Cent  of 
Pore  Space. 

Sandy  soil 

Clay  soil 

Fig.  9. — Spring-board  Compactor  Used  to  Secure  Uniform  Packing 
of  the  Soil.  The  can  or  tube  of  soil  is  placed  at  the  middle  of 
the  board  and  the  weight  on  the  standard  to  the  left  is  dropped 
a  definite  number  of  times  from  a  fixed  ))oint. 

Discussion:  The  large  amount  of  water  which  a  can 
will  hold  after  it  is  already  filled  with  dry  soil  serves  to 
bring  out  the  fact  that  only  about  half  of  the  soil  is  occu- 


TO  DETERMINE  THE  PORE  SPACE  IN  SOILS       19 

pied  by  the  soil  particles,  the  remainder  being  occupied  by 
water  when  the  soil  is  very  wet  or  by  air  when  it  is  per- 
fectly dry.  For  the  best  growth  of  crops  the  space  not 
occupied  by  the  soil  particles  should  be  divided  about 
equally  between  water  and  air.  If  the  space  becomes 
entirely  filled  with  water,  crops  will  not  thrive,  since  their 
roots  will  not  be  able  to  get  the  air  necessary  for  their 
growth.  Sandy  soil  has  larger  spaces  between  the  indi- 
vidual soil  particles,  but  the  total  amount  of  pore  space  is 
less  in  the  sandy  soil  than  in  the  clay  soil. 


EXERCISE    A-9.     TO    DETERMINE    THE    WEIGHT    OF 

SOIL   PER   CUBIC   FOOT. 

Equipment:  Balance;  brass  cylinder*  or  quart  can; 
samples  of  sandy  loam  and  clay  soils. 

Method:  Fill  the  quart  can  with  the  dry  sandy  loam 
and  compact  by  tapping  it  lightly  on  the  desk  four  times. 


Fig.   10. — A  very  good  Balance  of  this  Type  can  be  Purchased  for 

about  $8.00. 

Stroke  off  the  soil  level  with  the  top  of  the  can  and  weigh. 
Subtract  the  weight  of  the  empty  can. 

Calculate  the  capacity  of  the  can  in  cubic  inches  and 
from  the  weight  of  the  dry  soil  determine  the  weight  of 
one  cubic  foot. 

*  Brass  cylinders  for  this  exercise  may  be  purchased  from  labora- 
tory supply  houses  at  a  cost  of  about  $1.00  each. 

20 


WEIGHT  OF  SOIL  PER  CUBIC  FOOT 


21 


Calculate  the  weight  of  an  acre  of  this  soil  to  the  depth 
of  one  foot.     This  will  give  the  weight  of  an  acre-foot. 

Repeat  the  determination  for  the  clay  soil  and  record 
the  results  in  both  cases  in  the  following  table: 


Weight  of  Can 

of    Soil    in 

Grams  or 

Ounces. 

Capacity  of  Can 

in  Cubic 

Centimeters 

or  Inches. 

Weight  of  a 
Cubic  Foot. 

Weight  of  an 
Acre  Foot. 

Sandy  loam. . 

Clay.. 

Discussion:  The  weight  of  a  given  volume  of  soil 
depc;nds  very  largely  upon  the  amount  of  organic  matter 
present — the  greater  the  proportion  of  organic  matter  the 
lighter  the  weight  of  the  soil.  The  extent  to  which  the 
soil  is  compacted  also  influences  the  volume  weight. 


EXERCISE   A-10.     TO    STUDY    SOIL    GRANULATION. 

Equipment:  Three  shallow  pans;  sample  of  heavy 
clay  soil. 

Method:  Fill  each  of  three  pans  nearly  level  full  with 
dry  clay  soil.  To  the  first  pan  add  all  the  water  which 
it  will  hold,  continuing  to  pour  on  water  as  it  soaks  in, 
while  working  the  soil  with  the  fingers  or  with  a  stick. 
Over  the  second  pan  sprinkle  one-half  cup  of  water.  Leave 
the  third  pan  untreated.  Place  all  three  pans  near  a 
stove  or  in  the  sun,  and  dry  thoroughly.  Compare  the 
size  of  the  lumps  of  soil  in  the  pans  to  which  water  was 
added.,  Which  crumbles  more  easily  between  the  fmgers? 
Which  is  more  like  a  field  in  good  tilth?  What  happened 
to  the  first  pan? 

Discussion:  The  fine  rock  particles  in  a  pile  of  clean 
sand  always  remain  separate,  but  the  very,  very  fine  par- 
ticles of  rock  which  form  the  soil  stick  together  to  form 
crumbs  or  granules.  When  these  granules  are  comparativel}^ 
small  and  easily  crushed,  the  soil  is  said  to  be  ivcll  granulated. 
Large  hard  granules  are  called  clods.  When  a  large  amount 
of  water  is  added  to  a  clay  soil,  the  soil  becomes  "  puddled  " 
or  "  run  together,"  and  clods  are  formed.  Similarly,  if  a 
wet  clay  soil  is  compacted  by  the  feet  of  men  or  horses, 
or  if  it  is  plowed  when  too  wet,  hard  clods  are  formed. 

22 


EXERCISE  A-11.     TO  STUDY  THE  EFFECT  OF  FREEZING 
AND    THAWING    UPON    SOIL    GRANULATION. 

Equipment:     Shallow  pans;  some  clay  soil. 
Method:     Using  heavy  clay,  make  up  two  mud  balls 
to  about  the  consistency  of  putty.     Place  one  on  a  shelf 


Fig.  11. — ^Running  Water,  Freezing  and  Thawing,  and  the  Roots  of 
Trees  are  Powerful  Agencies  in  the  Breaking  Down  of  Rock  to 
Form  Soil. 


to  dry  and  the  other  outside  on  the  window  sill  where 
it  will  be  frozen.  Arrange  to  have  the  latter  alternately 
freeze  and  thaw  each  day  for  a  week  or  longer.  When 
both  are  dry  crush  them  with  the  hands.  Which  breaks 
the  more  easily? 

23 


21     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

Discussion:  The  freezing  of  water  is  one  of  the  natural 
agencies  which  plays  an  important  part  in  the  breaking 
up  of  the  rocks  to  make  soil.  This  same  force  can  be 
utilized  to  good  advantage  every  year  by  the  farmer  through 
the  practice  of  fall  and  winter  plowing.  Heavy  clay  soils 
b}^  this  practice  can  be  made  more  loose  and  friable.  Ex- 
posure of  the  plowed  land  to  the  action  of  freezing  and 
thawing  is  especially  desirable  where  the  soil  has  become 
hard  and  cloddy,  as  the  result  of  plowing  it  too  wet,  or  by 
the  trampling  of  livestock.  The  hard  clods  absorb  water 
which,  on  freezing,  expands  and  bursts  them  apart. 


EXERCISE   A-12.     TO    SHOW   THAT  SOME   SOILS    CAN 
HOLD    MORE    WATER   THAN    OTHERS. 

Equipment:  Four  funnels;  muslin  or  cheese  cloth; 
scissors;  well  rotted  manure;  four  graduated  cylinders  or 
bottles;  funnel  holder;  sand;  loam,  and  clay  soil. 

Method:  Plug  each  funnel  lightly  on  the  inside  with  a 
piece  of  cotton  or  cloth.  Fill  the  funnels  as  follows:  (1) 
sand,  (2)  loam,  (3)  clay,  (4)  one-half  sand  and  one-half 
manure.  Arrange  the  funnels  in  the  rack  with  their  stems 
in  the  mouths  of  the  bottles.  Very  slowly  pour  over  each 
funnel  exactly  eight  ounces  (one-half  pint)  of  water.  Allow 
to  stand  till  the  drip  ceases  and  read  the  amount  of  water 
in  each  bottle.  Record  these  readings  and  subtract  them 
from  the  amount  poured  into  each  funnel.  What  do 
these  differences  represent? 


Mixture  number. 


Amount  poured  in. 


Amount  in  bottle. 


Amount  held  in  soil. 


12  3 


Discussion :  The  capacity  of  soils  to  hold  water  depends 
upon  the  size  of  the  particles  and  the  amount  of  organic 
matter.     In  clay  soils  it  is  increased  by  granulation.     Clay 

25 


26     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

soils  can  hold  more  water  because  the  individual  spaces 
between  the  particles  are  smaller  and  the  total  amount  of 
space  is  larger,  than  in  other  soils.  Muck  and  clay  soils 
will  hold  the  largest  amount  of  water  and  sandy  soils  the 


-Cheesecloth 


-Perforated 
bottom 


Fig.  12. — Funnels  and  Gradu-  Fig.    13. — Brass  Cylinder  Used   to 

ated    Bottles  Used    to  Show  Measure  the    A\'ater-holding  Ca- 

that  Some  Soils   can   Retain  pacity  of  Soils. 
more  Water  than  Others. 


least.  The  supply  of  water  is  the  most  important  single 
factor  in  the  growth  of  plants.  Consequently,  the  extent 
to  which  different  soils  retain  moisture  deserves  careful 
study. 


EXERCISE  A-13.     TO   SHOW  THAT  PLANTS  GIVE   OFF 
MOISTURE  THROUGH  THEIR  LEAVES. 

Equipment:     Small   potted    plant;    wide-mouthed  jar; 
piece  of  cardboard;  wax.* 

Method:  Use  a  plant 
which  is  at  least  three  or 
four  inches  high  and  grow- 
ing in  a  flower  pot  or 
tomato  can.  Cut  a  slit  in 
the  cardboard  from  the 
middle  of  one  side  to  the 
center,  and  place  the  card- 
board around  the  plant- 
Seal  up  the  sht  in  the  card- 
board with  wax.  Now  in- 
vert the  glass  jar  over  the 
plant  and  place  in  a  sunny 
window.  How  do  the  drops 
of  water  get  into  the  glass 
jar? 

Discussion:    Plants   are 
constantly  giving  off  water 
from    their    leaves.       The   Fig.  14. 
k'-gest     amount     is     evap- 

*  Beeswax,  paraffin,  or  graft- 
ing wax  will  be  found  quite  satis- 
factory. 


Potted  Plant  AiTanged  to 
Show  that  Plants  Give  off  Moist- 
ure through  their  Leaves.  If 
placed  in  a  sunny  window,  drops 
of  moisture  soon  coUect  on  the  in- 
side of  the  can. 


27 


28     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

orated  in  the  hot  sun  and  when  an  abundance  of  water 
is  suppUed  to  the  roots.  Sometimes  in  a  drouth  more 
water  is  evaporated  from  the  leaves  than  is  being  taken  in 
by  the  roots.  If  this  is  continued  for  some  time  the  plant 
wilts.  This  reminds  us  that  the  water  in  plants  gives  the 
soft  stems  and  leaves  their  stiffness.  All  the  food  which 
the  plant  takes  from  the  soil  must  first  be  dissolved  in 
water.  It  is  estimated  that  900  tons  of  water  are  evap- 
orated by  each  acre  of  corn  plants  during  the  growing  season. 


EXERCISE  A-14.     TO  SHOW  THE  EFFECT  OF  SOIL  AIR 

UPON    PLANT    GROWTH. 

Equipment:  Two  tumblers,  or  quart  cans;  several 
grains  of  corn. 

Method:  Fill  two  tumblers  within  a  half  inch  of  the 
top  with  rich  soil.  Plant  in  each  three  kernels  of  corn. 
Water  tumbler  No.  1  only  enough  each  day  to  keep  the 
soil  moist.  Keep  water  in  the  second  tumbler  so  that  it 
stands  a  little  above  the  surface  of  the  soil.  Fill  in  the 
following  blanks: 


No.  1. 

No.  2. 

Dat.p  of  nlantinsr           

T)ato  first  nlant  ud             

Avp   VipicrVit  1  wk    flftpf  fiominsi!  ud 

What  kept  the  corn  in  one  tumbler  from  growing  as 
well  as  that  in  the  other?  W^hat  became  of  the  air  in  the 
soil  in  tumbler  No.  2? 

Discussion:  For  the  best  growth  of  crops  the  space 
not  occupied  by  soil  particles  should  be  divided  equally 
between  air  and  water.  If  this  space  becomes  entirely 
filled  with  water,  crops  will  not  thrive,  since  their  roots 
will  not  be  able  to  get  the  air  necessary  for  plant  growth. 

29 


30     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

Some  plants,  such  as  the  cypress  and  the  water  hly,  have 
special  structures  which  enable  them  to  obtain  air  from 
the  water  while  their  roots  are  entirely  submerged,  but 
our  common  field  plants  do  not  have  this  abiUty. 


EXERCISE  A-15.     TO  SHOW  HOW  THE  TEMPERATURE 
OF   THE    SOIL   IS   AFFECTED    BY   THE    SLOPE. 

Equipment:  Three  boxes,  6''X12''X12'';  three  ther- 
mometers;* soil  sample. 

Method:  Nmiiber  the  boxes  1,  2,  and  3,  fill  with  the 
same  kind  of  soil  and  set  them  in  the  sunhght,  side  by 


Fig.  15. — Arrangement  of  Boxes  to  Show  the  Effect  of  Slope  upon 

the  Temperature  of  the  Soil. 


side.  Arrange  the  boxes  so  that  No.  1  will  stand  level, 
No.  2  slope  toward  the  south  (four  inches  slope  to  the 
foot)  and  No.  3  slope  toward  the  north  at  the  same  angle. 

*  The  thermometers  should  be  tested  by  placmg  the  three  side  by 
side  in  a  tumbler  of  water  and  after  stirring  the  water  for  a  few  minutes 
compare  the  readings  on  the  thermometer  scales.  If  they  do  not  read 
the  same  a  suitable  correction  must  be  applied. 

31 


32      FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

Place  a  thermometer  in  each  with   the  bulb   covered  with 
soil.     Take  readings  every  two  hours  during  the  day. 


TEMPERATURE 

RECORD 

Hour    



South  slope 

North  slope 

Level 

List  the  three  surfaces  in  the  order  of  their  temperature. 
What  location  would  you  seek  for  an  early  garden  plot? 

Discussion:  The  temperature  of  the  soil  is  affected  by 
the  slope,  because  in  one  case  a  given  amount  of  the  sun's 
heat  must  warm  a  larger  area  of  soil  than  in  another. 
When  the  slope  is  towards  the  sun  the  soil  stands  more 
nearly  at  right  angles  to  the  sun's  rays,  but  when  the  sur- 
face is  level  or  slopes  away  from  the  sun,  it  is  inclined  away 
from  the  direct  rays.  The  same  amount  of  heat  must  then 
warm  a  larger  area.  This  increase  in  area  may  be  shown 
by  sawing  off  a  board  at  right  angles  and  then  at  an  obtuse 
angle,  and  measuring  the  cross-section  each  time. 


EXERCISE  A-16. 


TO  STUDY  THE  NECESSITY  FOR  SOIL 
DRAINAGE. 


Equipment:  Two  one-quart  tin  cans;  a  graduated 
cylinder  or  bottle;  a  one-foot  rule;  several  grains  of  corn; 
a  sample  of  loa-n  soil. 

Method:  Make  eight  holes  in  one  can  by  driving  a 
nail  through  the  bottom.  Stand  this  can  on  blocks  in  a 
saucer.  Fill  both  cans  with  loam  to  within  one  inch  of 
the  top  and  plant  three  grains  of  corn  in  each.  Each  day, 
pour  water  upon  the  surface  of  the  soil  in  the  tight  can 
until  it  stands  at  the  surface,  noting  the  amount  used  each 
time.  At  the  same  time  add  the  same  amount  of  water  to 
the  other  can,  using  the  graduated  bottle  to  determine 
the  amount  added.  As  soon  as  the  corn  appears  above  the 
surface  measure  its  height  every  other  day,  recording  the 
average  height  of  the  three  plants  in  each  can.  The  height 
may  be  regarded  as  the  distance  from  the  surface  of  the 
soil  to  the  tip  of  the  uppermost  leaf. 


Average  Height  of  Plants  on  the  Following  Dates: 

Can  without  holes . 

Can  with  holes. .  .  . 

■ 

From  this  exercise  what   do  you   conclude   as   to   the 

33 


34     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

relative  length  of  time  which  would  be  required  for  corn 
to  come  up  in  a  drained  and  in  an  undrained  field? 


Fig.  16. — Corn  Planted  the  Same  Day.  Tumbler  of  soil  to  the 
left  kept  saturated  while  the  one  to  the  right  is  only  about 
half-saturated  with  water. 


What  effect  does  drainage  have  upon  the  air  in  the  soil? 
Discussion:     The  rain  which  falls  on  the  fields  would 


TO  STUDY  THE  NECESSITY  FOR  SOIL  DRAINAGE    35 

in  time  completely  saturate  the  soil  if  no  drainage  were 
possible.  The  more  nearly  level  the  land  the  more  readily 
does  the  rain  pass  into  it.  During  a  long-continued  rain 
the  water  soaks  into  the  soil  until,  like  a  blotter  or  a  sponge, 
it  can  hold  no  more.  Then  the  excess  of  water  will  flow 
over  the  surface  to  the  lowest  points  in  the  field  and  finally 
join  the  creeks  and  rivers  which  are  a  part  of  Nature's 
great  drainage  system. 

The  water  which  has  soaked  into  the  soil  gradually 
passes  into  the  subsoil  and  eventually  finds  its  way  to  the 
streams.  If  the  soil  is  a  loam  with  an  open  subsoil,  this 
natural  drainage  will  be  sufficient.  However,  in  heavy 
loams  and  in  clay  soils  Nature  does  her  work  too  slowly 
to  be  of  immediate  benefit.  Then  it  is  that  w^e  should 
supply  artificial  drainage  in  the  form  of  tile  to  carry  away 
the  surplus  water  more  promptly  and  thus  assist  Nature. 


EXERCISE  A-17. 


A  STUDY  OF   "  WARM  "  AND  "  COLD  " 
SOILS. 


Equipment:  Dry  loam  soil;  two  thermometers;  two 
flower  pots  or  quart  cans;  a  beaker  or  tumbler. 

Method:  (a)  Tie  a  piece  of  muslin  cloth  around  the 
bulb  of  one  thermometer  and  suspend  it  over  a  tumbler 
with  the  lower  end  of  the  cloth  dipping  into  the  water, 
but  the  bulb  one  inch  above  the  surface.  Suspend  the 
other  thermometer  in  the  air  near  the  tumbler.  At  the 
end  of  ten  minutes  read  both  thermometers  and  take  the 
temperature  of  the  water.     Record  as  follows: 


Degrees. 

Temperature  of  the  air 

Temperature  of  the  wet  bulb .  . 

Temperature  of  the  water 

Why  is  the  temperature  of  the  wet  bulb  lower  than  that 
of  the  air  or  water? 

(b)  Fill  two  flower  pots  with  the  dry  soil  and  add 
sufficient  water  to  one  to  thoroughly  wet  the  soil.  Insert 
the  bulb  of  one  thermometer  to  the  depth  of  one-half  inch 
into  the  wet  soil  and  the  other  to  the  same  depth  into  the 
dry  soil.  Make  a  reading  of  both  thermometers  at  the  end 
of  fifteen  minutes. 

36 


A  STUDY  OF  "WARM"  AND  "COLD"  SOILS       37 

Discussion:  Tile-drained  soils  and  sandy  soils  with 
good  natural  drainage  warm  up  more  rapidly  in  the  spring 
than  poorly  drained  soils.  Why?  Sandy  land  is  com- 
monly spoken  of  as  a  warm  soil,  while  clay  is  regarded  as 
a  cold  soil.  Well-drained  sandy  soil  is  used  for  the  growing 
of  early  truck  crops.     Why? 

Plowing  or  stirring  the  soil  in  the  early  spring  hastens 
evaporation  and  as  soon  as  the  surface  becomes  dry  the 
soil  begins  to  warm  up  rapidly. 


EXERCISE  A-18.     TO  STUDY  THE  OPERATION  OF  TILE 

DRAINS. 

Equipment:     Drainage  apparatus;  dipper;  glass  tumbler; 
sample  of  sandy  loam  soil. 

Method:     Fill  the  drainage  apparatus  to  within  an  inch 


Fig.  17. — To  the  Left,  a  Tin  Can  Arranged  to  Show  the  Operation 
of  Tile  Drains.     To  the  Right  is  the  Grahani-McCall  Apparatus. 

of  the  top  with  sandy  soil.  If  a  drainage  apparatus  is 
not  available,  a  tin  can  may  be  used  after  having  punched 
two  holes  in  the  side  as  shown  in  the  diagram. 

Slowly  pour  water  over  the  surface  of  the  soil  and  note 
the  result. 

To  operate  the  Grahara-McCall  apparatus,  fill  the  ves- 

38 


TO  STUDY  THE  OPERATION  OF  TILE  DRAINS     39 

sel  with  soil  and  pour  on  water  at  regular  intervals,  giving 
it  time  to  soak  into  the  soil.  The  water,  instead  of  coming 
out  at  the  tubes,  will  pass  downward  through  the  soil 
until  the  solid  bottom  is  reached,  when  a  water-table  of 
free  hquid  will  be  formed  at  a  level  indicated  by  the  height 
of  water  in  the  glass  stand-pipe.  When  the  free  water  has 
risen  to  the  first  opening  it  will  pass  outside  the  vessel, 
thus  proving  that  a  tile  drain  placed  as  low  as  soil  con- 
ditions will  permit  removes  free  water  before  one  placed 
nearer  the  surface. 

Discussion:  The  lower  tube  in  the  drainage  apparatus 
or  the  lower  hole  in  the  can  represents  a  deep  tile  drain, 
while  the  upper  tube  or  hole  represents  a  shallow  drain. 
The  object  of  the  tile  is  to  prevent  the  rise  of  the  ground 
vvater  surface  which  interferes  with  the  root  development 
of  the  plants. 


EXERCISE  A-19.     A  STUDY  OF  SOIL  TEMPERATURE. 

Equipment:     Two  or  more  thermometers;  a  soil  auger. 

Method:  For  this  exercise  select  a  bright  clay  about 
the  time  spring  plowing  begins.  Go  to  a  nearby  field 
and  take  the  temperature  by  burying  the  bulb  of  the  ther- 
mometer to  the  depth  of  three  inches.  To  avoid  breaking 
the  thermometer,  first  make  a  hole  in  the  soil  to  the  proper 
depth  with  a  small  stick  or  lead  pencil  and  then  insert 
the  thermometer.  The  reading  should  not  be  taken  until 
after  the  thermometer  has  been  in  contact  with  the  soil 
about  fifteen  minutes.  While  waiting  to  make  this  read- 
ing, bore  a  hole  to  the  depth  of  three  feet  and  lower  the 
other  thermometer  until  the  bulb  rests  on  the  bottom. 
At  the  end  of  fifteen  minutes  the  thermometer  should  be 
drawn  to  the  top  and  read  immediately.  Take  the  tem- 
perature at  the  three-inch  depth,  (1)  of  a  north  and  of  a 
south  slope;  (2)  of  unplowed  and  freshly  plowed  land;  (3)  of 
grass  land  and  a  cultivated  field.  Record  all  temperatures 
and  discuss  the  results. 


Reading  of 
Thermonittcr, 

North  slope 

South  slope 

Unplowed  field 

Plowed  field 

Grassland 

Cultivated  field 

40 


A  STUDY  OF  SOIL  TEMPERATURE  41 

Discussion:  Early  in  the  spring  the  surface  soil  is 
usually  cooler  than  the  deeper  layers;  south  slopes  are 
warmer  than  north  slopes;  cultivated  fields  are  warmer 
than  uncultivated.     Why? 


EXERCISE  A-20.     TO  DEMONSTRATE  THE  MOVEMENT 

OF    WATER   IN    THE  SOIL. 

Equipment:  Two  tumblers;  a  saucer;  a  strip  of 
blotting  paper,  and  some  fine  dry  soil. 

Method:  Fill  one  of  the  tumblers  with  water  and 
suspend  above  it  the  strip  of  blotting  paper  with  the  lower 
end  dipping  into  the  water.  Fill  the  second  tumbler  with 
fine  dry  soil  and  sprinkle  three  or  four  spoonfuls  of  water 
over  the  surface.  Make  a  mound  of  dry  soil  in  the  center 
of  the  saucer  and  pour  water  into  the  saucer  until  it  stands 
one-half  inch  deep. 

Describe  what  happened  in  each  case. 

Discussion:  The  force  which  causes  the  water  to 
move  uphill  in  the  blotting  paper  and  in  the  saucer  of  soil 
is  called  capillarity  and  the  water  which  moves  in  this 
way  is  known  as  capillary  water.  The  capillary  movement 
of  the  water  is  usually  upward,  but  when  a  light  shower 
falls  on  the  surface  of  a  dry  soil  the  movement  will  be 
downward  and  laterally  as  shown  in  the  second  tumbler. 

During  the  growing  season,  water  is  moving  by  capillarity 
from  the  deepen-  layers  of  soils  toward  the  surface.  If 
allowed  to  do  so,  much  of  the  moisture  stored  in  the  soil 
will  pass  on  up  through  the  surface  layer  and  be  evaporated 
without  having  been  of  any  service  to  the  plants  growing 
in  the  soil.  To  prevent  this  loss  we  practice  shallow,  fre- 
quent cultivation,  wliich  keeps  a  protective  covering  of 
loose  soil  over  the  surface. 

42 


FffOM  1    /  f     I 


^  WATER  STORED  IN  SO/L  ^      ^  WATER  STORED  IN  SO/L     ^== 


Fig.  18. — Movement  of  Soil  Moisture.  To  the  right  the  rain  is  soaking  into  the  soil. 
It  passes  down  into  it  by  gravity  and  is  stored  for  future  use.  During  dry 
weather  the  water  moves  upward  by  capillarity  to  supply  the  plants  as  shown 
to  the  left.  On  one  side  of  the  plant  a  mulch  prevents  the  loss  of  moisture, 
while  on  the  other  side  the  water  is  being  lost  by  evaporation  at  the  crusted  sur- 
face. The  moisture  saved  by  the  mulch  is  free  to  e  iter  the  plant  with  dissolved 
material,  which  it  leaves  behind  as  it  evaporates  from  the  leaf  surface. 

43 


EXERCISE  A-21.     TO   COMPARE  THE   MOVEMENT   OF 
WATER   THROUGH    DIFFERENT    SOILS. 

Equipment:  Four  tall  brass  cylinders  or  tin  cans  with 
perforated  bottoms;  four  graduated  bottles;  cheesecloth; 
samples  of  sand,  muck  and  clay  soil. 

Method:  Number  the  four  cylinders  or  cans  and  cover 
the  bottom  of  each  with  a  layer  of  cheese  cloth.  After 
supporting  them  over  the  graduated  bottles,  fill  the  cans 
to  within  one  inch  of  the  top,  as  follows:  No.  1,  sand; 
No.  2  mixture  of  half  sand  and  half  muck;  No.  3  clay; 
No.  4  mixture  of  half  clay  and  half  sand. 

Taking  each  can  separately,  slowly  pour  water  on  the 
surface  of  the  soil  and  note  the  time  required  for  the  water 
to  come  through  and  l^egin  to  drip  from  the  bottom. 
Continue  to  pour  on  water  and  measure  the  amount 
which  comes  through  during  the  next  ten  minutes.  If  the 
sand  is  coarse  it  may  be  necessary  to  shorten  the  time 
to  one  minute  for  that  material. 


No.  1. 

No.  2. 

No.  3. 

No.  4. 

Tiine  to  come  through. 

Amount  in  10  minutes. 

What  kind  of  soil  is  most  likely  to  drain  out  naturally? 
What  kind  of  soil  reciuires  tile  drainage? 


44 


WATER  THROUGH  DIFFERENT  SOILS  45 

Discussion:  After  a  rain,  when  the  capillary  or  film 
capacity  of  the  soil  has  been  reached,  the  free  or  gravi- 
tational water  percolates  down  to  the  subsoil  and  runs 
away.  The  rate  at  which  this  free  water  gets  out  of  the 
zone  of  the  roots  is  called  the  rate  of  percolation.  This 
rate  depends  upon  the  fineness  of  the  particles,  the  degree 
of  granulation,  and  the  content  of  organic  matter.  In 
soils  in  which  the  particles  are  comparatively  fine  and  the 
spaces  between  the  particles  correspondingly  small,  the 
percolation  is  slow.  When  a  fine  soil  is  well  granulated, 
the  larger  spaces  between  the  granules  permit  a  more  rapid 
flow.  This  is  desirable,  since,  to  have  the  soil  saturated 
long  is  injurious  to  crops.  On  the  other  hand  in  some 
sandy  soils  percolation  may  he  so  rapid  as  to  cause  leach- 
ing, i.e.,  carr3dng  away  of  the  plant  nutrients.  The  addi- 
tion of  organic  matter  tends  to  prevent  leaching. 


EXERCISE  A-22.  TO  SHOW  THE  EFFECT  OF  A  LOOSE 
SURFACE  UPON  THE  RATE  AT  WHICH  THE  RAIN 
WILL  SOAK  INTO  THE  SOIL. 

Equipment:  Two  quart  cans;  a  graduate;  sufficient 
moist  garden  or  field  soil  to  fill  the  two  cans. 

Method:  Fill  the  two  cans  to  within  one  inch  of  the 
top  with  the  moist  soil.  Firmly  compact  the  surface  of 
the  soil  in  one  can  and  leave  the  surface  of  the  other  loose. 
Pour  an  equal  amount  (4  ounces)  of  water  on  the  surface 
of  each  and  note  the  time  it  takes  it  to  disappear  into  the 
soil.  Which  takes  in  the  water  more  rapidly,  the  loose  or 
the  compacted  surface? 


Time  Required  for  Water 
to  Disappear. 

Loose  surface 

Comi)acted  surface. .  . 

Discussion:  When  rain  falls  upon  the  surface  of  a 
field  a  part  of  the  water  soaks  into  the  soil  and  another 
part  runs  off  the  surface.  If  the  surface  is  dry  and  hard, 
a  very  large  part  of  the  rain  runs  off  and  only  a  small  quan- 
tity enters  the  soil.  The  part  which  runs  off  the  surface 
is  not  only  entirely  lost  to  the  crop,  but  it  also  washes  the 
surface  and  carries  away  with  it  a  large  amount  of  plant 

46 


RATE  AT  WHICH  RAIN  WILL  SOAK  INTO  SOIL    47 

food.  Observe  what  happens  when  a  hard  rain  falls 
on  a  loose,  mellow  garden,  and  compare  with  what  takes 
place  on  a  hard  path  during  a  heavy  rain.  Thrifty  farmers 
try  to  keep  their  soil  mellow  and  loose  on  the  surface  so 
that  it  will  absorb  and  hold  sufficient  w^ater  to  carry  the 
plants  through  the  dry,  hot  part  of  the  season.     Persistent 


Fig.    19. — This  Soil  should  be  Cultivated  at  Once  to  Prevent  the 
Loss  of  Moisture  through  the  Shrinkage  Cracks. 

tillage,  which  keeps  the  surface  loose,  enables  the  rainfall 
to  enter  the  soil  easily.  Frequent  shallow  cultivation  also 
serves  in  a  dry  time  to  prevent  the  loss  of  moisture  from 
below.  The  soil  which  is  stirred  forms  a  covering  or  dust 
mulch  which  protects  the  deeper  soil  and  lessens  the  loss 
by  evaporation  at  the  surface, 


EXERCISE    A-23.     TO    STUDY    THE  FORMS    OF    SOIL 

MOISTURE. 


.^^ 


Equipment:*    Balances;  drying  oven;  soil  auger;  sample 

boxes. 

Method :  With  the  soil  auger  secure 
samples  of  soil  at  a  depth  of  six, 
eighteen,  and  thirty  inches.  Transfer 
the  samples  at  once  to  tight  tin  boxes 
with  lids.  As  soon  as  possible  weigh 
the  boxes  and  contents.  Remove  the 
lids  and  let  the  soil  dry  in  the  air  for 
one  week,  then  weigh.  Continue  the 
drying  until  constant  weight  is  at- 
tained. 

What  does  the  loss  in  weight 
Fig.  20. — Soil  Sample-  represent?  Does  this  soil  still  contain 
case  Provided    with  any  moisture? 

Place  the  samples  in  an  oven  with 
the  lids  off  the  boxes  and  dry  for  two 
days.     Weigh  and  record  the  weights. 

*  The  balance  shown  in  Exercise  7  or  the  one  shown  in  Exercise 
9  may  be  used.  A  one-burner  gasoline  or  kerosene  stove  with  a 
small  baking  oven  may  be  used.  The  flame  should  be  regulated  to  kecj) 
the  temperature  at  about  105°  C.  or  212°-215°  F. 

A  soil  auger  may  be  purchased  from  an  implement  firm  or  it  may  be 
constructed  by  a  local  blacksmith  by  welding  a  length  (three  feet)  of 
iron  pipe  onto  the  shank  of  a  common  1^  or  1 2-inch  wood  auger. 
Tin  salve-boxes  make  very  satisfactory  soil  containers. 

48 


Seamless  Tin  Boxes 
for  Use  in  Collecting 
Field  Samples. 


TO  STUDY  THE  FOEMS  OF  SOIL  MOISTURE       49 

If  the  weight  changed  in  the  oven  how  do  you  account 
for  the  change?  Fill  out  the  table  given  at  the  end  of 
the  exercise  and  write  over  the  fourth  and  fifth  columns 
the  name  of  the  kind  of  soil  moisture  which  each  represents. 
What  form  of  soil  moisture  is  it  that  fills  a  post  hole  as  soon 
as  it  is  dug?  Which  sample  contained  the  highest  per  cent 
of  moisture. 


Sample. 

1 

Original 
Weight. 

2 

Air-dry 
Weight. 

3 

Oven-dry 
Weight. 

4 

Loss  in 

Air. 

5 

Loss  in 
Oven. 

1 

2 

3 

Fig.  21. — A  Gasoline  Stove  Oven,  Galvanized  Iron  Trays,  and  Tin 

Dishes  for  Drying  Soil  Samples. 


50     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

Discussion:  Moist  soil  as  we  find  it  under  ordinary 
conditions  in  the  field  holds  the  water  as  a  thin  film  around 
the  soil  grains.  This  form  of  moisture  is  given  the  name 
film  moisture,  because  of  the  fact  that  it  forms  a  film  over 
the  surface  of  the  tiny  soil  particles.  This  moisture  is 
available  for  the  use  of  the  plants  that  may  be  growing  in 
the  soil. 

If  a  handful  of  this  moist  soil  is  spread  on  a  board  for 
several  days  and  allowed  to  dry,  it  will  have  the  appear- 
ance of  containing  no  moisture  at  all.  The  film  moisture 
will  be  gone,  but  the  hygroscopic  moisture  will  still  be 
present.  This  form  of  moisture,  which  is  not  available  to 
plants,  varies  with  the  moisture  in  the  air  and  cannot  be 
driven  out  without  heating  the  soil. 

The  third  form  in  which  moisture  occurs  in  the  soil  is 
called  free  or  gravitational  water.  This  form  is  seen  seep- 
ing out  of  the  banks  of  rivers  and  smaller  streams. 


EXERCISE   A-24.     TO    STUDY   THE    CAPILLARY   MOVE- 
MENT   OF    SOIL    MOISTURE. 

Equipment:  Four  lamp  chimneys;  cheesecloth;  twine; 
tray  1"X4''X12"  ;  rack  to  support  chimneys;  samples  of 
clay,  loam,  and  sandy  soils;   foot  rule. 

Method :  Tie  a  piece  of  cloth  over  the  small  end  of  each 
chimney.  Number  and  fill  them  as  follows:  (1)  sand,  (2) 
loam,  (3)  clay,  (4)  half  sand  and  half  clay.  Place  the  chim- 
neys in  the  rack  and  keep  the  pan  filled  with  water.  Meas- 
ure and  record  the  height  of  the  water  in  each,  after  a  half 
hour,  one  hour,  and  every  twenty-four  hours  for  a  week. 

Record  your  data  as  follows: 


No. 

i  Hr. 

1  Hr. 

1  Day. 

2  Days. 

3  Days. 

4  Days. 

5  Days. 

6  Days. 

7  Days. 

1 

2 

3 

4 

In  which  kind  of  soil  did  the  water  rise  fastest  at  first? 
In  which  did  it  finally  stand  highest? 
Does  capillary  moisture  always  move  directly  upward? 
Discussion:     Water  rises  through  the  soil  in  the  same 
way  that  oil  rises  in  a  lamp  wick.     Throughout  the  growing 

51 


52      FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

season,  and  especially  in  dry  weather  when  the  level  of 
standing  water  is  many  feet  below  the  surface,  plant  roots 
are  supplied  by  capillary  moisture  which  is  moving  up 
through  the   soil.     The   depth  from  which  water   may  be 


Fig.  22. — Lamp  Chimneys  may  be  Used  to   Show  the  Capillary  Rise 

of  Moisture. 


raised  by  capillary  action  depends  upon  the  kind  of  soil. 
Clay  soils  bring  water  from  a  greater  depth  than  coarser 
soils.  Sandy  soil  is  sometimes  said  to  "  burn  out/'  because 
in  a  drouth  it  furnishes  little  or  no  water  to  the  plant, 
although  standing  water  is  but  a  few  feet  below  the  surface. 


EXERCISE  A-25.  TO  SHOW  THE  EFFECT  OF  PLOW- 
ING UNDER  COARSE  MATERIAL  SUCH  AS  MANURE, 
GREEN  COVER  CROPS,  OR  CLODS. 

Equipment:  Three  lamp  chimneys;  rack  to  support 
chimneys;  tray  1'X4"X12'';  cheese  cloth;  scissors;  twine; 
sample  of  sandy  loam  soil;   cut  straw;   soil  lumps  or  clocls. 

Method:  Cover  the  small  end  of  each  lamp  chimney 
with  a  piece  of  cloth  and  tie  it  on  with  the  twine.  Number 
and  fill  the  tubes  as  follows:  (1)  when  about  two-thirds 
full  add  enough  cut  straw  to  make  a  layer  one  inch  thick, 
and  complete  filling;  (2)  when  two-thirds  full  add  enough 
round  hard  clods  to  make  a  layer  about  one  inch  thick,  and 
complete  filhng;  (3)  fill  with  fine  soil.  Hang  the  tubes  in 
the  rack  with  their  lower  ends  resting  lightly  on  the  bottom 
of  the  tray  and  fill  the  pan  with  water.  At  the  end  of  four 
days  note  the  height  of  the  water  in  each  tube.  Since  the 
same  kind  of  soil  was  used  in  each  tube  would  you  not  ex- 
pect the  water  to  rise  to  the  same  height  in  each?  Explain 
the  cause  for  what  you  find. 

Discussion:  When  capillary  water  rises  in  the  soil  it 
passes  from  one  tiny  particle  to  another  which  lies  next  to 
it.  If  the  particles  are  separated  by  a  very  wide  space  or 
by  some  loose  substance  the  rise  of  water  is  stopped.  This 
may  happen  when  a  heavy  growth  of  green  material  like 
rye  is  plowed  under.  Harm  will  be  prevented  if  the  green 
material  is  thoroughly  cut  with  a  disc  before  being  turned 

under  and  the  furrows  turned  so  as  to  lap  and  not  lie  flat. 

53 


EXERCISE  A-26.  TO  SHOW  THE  EFFECT  OF  A  MULCH 
IN  PREVENTING  THE  LOSS  OF  MOISTURE  AT 
THE    SURFACE    OF    THE    SOIL. 

Equipment:     Balance;  sample  of  soil ;  dry  sand  or  dust; 
dipper;   shallow  tray. 


Fig.  23. — Home-made  Balance  Used  to  Show   the  Effect  of  a  Dry 

Earth  Mulch. 

Method:  Fill  one  can  to  within  one  inch  of  the  top 
with  moist  soil  and  the  other  can  to  within  two  inches  of 
the  top  with  the  same  soil.     Pour  dry  sand  or  dust  over  the 

54 


LOSS  OF  MOISTURE  AT  SURFACE  OF  THE  SOIL     55 

surface  of  the  second  can  to  the  depth  of  one  inch.  Place 
the  cans  on  the  scale  pans  or  suspend  them  from  the  arms 
of  the  balance  and  adjust  the  amount  of  soil  in  the  two  cans 
until  the  system  balances  and  the  arms  of  the  balance 
remain  horizontal. 

After  allowing  the  apparatus  to  stand  over  night,  it 
will  be  found  that  the  system  is  no  longer  balanced.  The 
soil  which  was  covered  with  the  dust  or  sand  has  lost  but 
little  moisture,  while  the  unprotected  surface  of  the  other 
soil  has  lost  a  much  larger  amount.  The  amount  of  water 
that  must  be  added  to  the  can  with  the  exposed  soil  surface 
to  restore  the  balance  represents  the  moisture  that  has  been 
saved  by  the  protective  covering  of  dust — the  dry  earth 
mulch.  Li  using  the  home-made  balance  the  bar  should 
be  held  in  a  horizontal  position  while  the  water  is  being 
added. 

Discussion:  Have  you  ever  noticed  how  moist  the  soil 
is  under  a  stone  or  a  board  even  when  the  surrounding 
ground  is  quite  dry?  The  stone  or  board  has  kept  the  air 
away  from  the  surface  of  the  soil  and  prevented  evapora- 
tion. When  shallow  cultivation  is  practiced,  the  thin 
layer  of  stirred  soil  soon  becomes  very  dry,  but  by  keeping 
the  air  away  it  serves  to  prevent  the  deeper  soil  from  losing- 
its  moisture  by  evaporation.  This  loose  blanket  or  mulch, 
as  it  is  called,  also  helps  to  absorb  rainfall  and  to  prevent 
it  from  running  off  the  surface. 


EXERCISE  A-27.  TO  STUDY  THE  WATER  LOSS  FROM 
CULTIVATED,  UNCULTIVATED  AND  MULCHED  SOIL 
SURFACES. 


Equipment:     Three   galvanized-iron  cylinders;    shallow 
Dan;  table  knife;  a  pair  of  scales  having  a  capacity  of  fifty 

pounds;  a  small  quantity  of  cut  straw; 
a  quantity  of  dry,  sifted  loam  soil. 

Method:  Number  the  three  cylin- 
ders and  fill  each  to  within  one  inch 
of  the  top  with  the  dry  soil.  Pour 
water  into  the  jacket  at  the  bottom 
until  the  soil  appears  moist  at  the 
surface.  This  will  probably  require 
several  hours,  but  the  experiment  will 
need  no  attention  during  this  time 
except  to  see  that  the  water  is  re- 
plenished in  the  jackets  from  time  to 
time.  It  is  a  good  plan  to  start  the 
exercise  in  the  afternoon  and  allow 
the  cylinders  to  stand  over  night  or 
until  the  next  period. 
After  the  water  has  reached  the  surface  of  the  soil  in 
all  of  the  cylinders  they  should  receive  the  following  treat- 
ment : 

No.  1.  Compact  the  surface. 

56 


Fig.  24. — Galvanized 
Iron  Mulch  Cylinder. 


WATER  LOSS  FROM  MULCHED  SOIL  SURFACES    57 

No.  2.  Remove  two  inches  of  soil  and  replace  with  cut 

straw. 
No.  3.  Remove  two  inches  of  the  surface  and  replace 
it  in  a  loose  condition. 
Care  should  be  taken  to  have  all  of  the  surfaces  at  the 
same  distance  below  the  top  of  the  cylinders.     Why?     The 
surface  of  No.  3  is  to  be  removed  to  the  shallow  pan  and 
mixed  before  it  is  returned  to  place.     It  should  then  be 
stirred  occasionally  to  keep  the  surface  in  a  loose  condition. 
As  soon  as  the  mulches  are  in  place,  fill  all  of  the  water 
jackets  to  the  same  level  and  weigh  each  cylinder.     Repeat 
the  weighings  every  other  day  for  a  week  and  record  the 
weights  in  the  accompanying  table: 


Cylin- 

Treatment. 

Weight  of  Cylinders  and  Soil. 

Total 

Water 

Loss. 

Tons 

der. 
No. 

First 
Day. 

Third 
Day. 

Fifth 
Day. 

Seventh 
Day. 

per 
Acre. 

1 

Compacted 

2 

Straw  mulch .... 

3 

Loose  soil  mulch . 

• 

Which  cylinder  lost  the  greatest  amount  of  water  by 
evaporation? 

How  does  the  farmer  and  gardener  make  use  of  soil  and 
straw  mulches? 

Discussion:  Any  covering  placed  upon  the  surface  of 
the  soil  to  prevent  or  lessen  evaporation  of  moisture  is  called 
a  mulch.  An  artificial  mulch  is  a  covering  of  straw,  leaves, 
sawdust  or  other  material  of  a  like  nature.     A  natural  mulch 


58      FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

is  the  layer  of  loose  soil  produced  by  frequent  shallow  cul- 
tivations. 

Artificial  mulches  are  sometimes  used  in  gardens  and  in 
small  truck  patches,  but  in  the  large  fields  the  natural 
mulch  is  the  only  practical  means  for  preventing  the  escape 
of  the  moisture  by  evaporation  at  the  surface  of  the  soil. 


EXERCISE  A-28.     TO   SHOW  THE  EFFECT  OF  DRAIN- 
AGE  UPON    SOIL   TEMPERATURE. 

Equipment:  Two  one-quart  tin  cans;  thermometer; 
loam  soil. 

Method:  Make  several  holes  in  the  bottom  of  one  can 
by  driving  a  nail  through  it.  Fill  each  can  with  the  same 
kind  of  soil.  Wet  the  soil  in  both  cans  thoroughly.  Push 
the  bulb  of  a  thermometer  one  inch  deep  in  each  can  and 
place  in  a  sunny  window.  Record  the  temperature  every 
two  hours,  continuing  the  readings  on  the  second  and  third 


First  Day. 

Second  Day. 

Third  Day. 

Time 

0 

2 

4 

6 

8 

0 

2 

4 

6 

8 

0 

2 

4 

6 

8 

Can  with  holes 

Tight  can 

How  does  the  temperature  of  the  soil  affect  the  growth 
of  crops. 

When  is  this  most  important?  What  would  you  do  for 
a  soil  that  is  wet  and  cold? 

Discussion:  If  we  were  to  place  a  pan  of  water  and  a 
pan  of  dry  soil  on  a  stove,  we  would  find  that  it  took  longer 
to  heat  the  water  to  a  given  temperature  than  the  dry  soil. 

59 


60     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

This  is  because  the  amount  of  heat  required  to  raise  the 
temperature  of  water  is  several  times  as  great  as  that  re- 
quired to  raise  the  temperature  of  soil.  Consequently, 
when  any  soil  contains  a  large  amount  of  water  it  is  warmed 
more  slowly  than  a  well-drained  soil,  which  has  been  relieved 
of  its  surplus  moisture. 


EXERCISE  A-29.     TO  SHOW  THE  INFLUENCE  OF  COLOR 
UPON    SOIL   TEMPERATURE. 

Equipment:  Box  4''X12''X24'';  two  thermometers; 
chalk  dust;  soot  or  lampblack;  twenty  grains  of  corn. 

Method:  Fill  the  box  with  moist  soil  and  plant  the 
corn  in  regular  rows.  Scatter  chalk  dust  over  one-half 
of  the  box  and  soot  or  lampblack  over  the  other  half  to 
the  depth  of  a  quarter  of  an  inch.  Insert  the  bulb  of  a 
thermometer  about  one-half  inch  beneath  the  surface  in 
the  middle  of  each  half  of  the  box.  On  the  first  day  read 
the  thermometers  every  two  hours  from  early  in  the  morning 
until  two  hours  after  sunset.  Make  a  record  of  the  num- 
ber of  corn  plants  which  come  up  in  each  half,  on  the  day 
when  they  can  first  be  seen. 

TEMPERATURE. 


Hour 

Light  surface 

Dark  surface 

PLANTS   UP. 


Day 

Light  surface 

Dark  surface 

61 


62     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

What  influence  does  color  have  on  the  temperature  of  the 
soil?  When  is  this  difference  greatest?  How  would  the 
addition  of  organic  matter  affect  the  temperature  of  a  soil? 
Discussion :  The  color  of  soil  is  due  to  three  things : 
(1)  The  color  may  come  from  the  original  rock  particles 


Fig.  25. — Corn  Planted  the  Same  Day.      Dark  surfaces  absorb 

more  heat  than  light  objects. 

of  which  the  soil  is  formed.  An  example  of  this  is  found 
in  white  sandy  soil  from  clear  quartz  sand.  (2)  The  color 
usually  comes  from  material  which  sticks  to  the  particles. 
The  coloring  material  may  be  either  iron  compounds  or 
organic  matter  or  both.  Red,  yellow,  blue,  and  gray 
soils  are  colored  by  some  form  of  iron,  and  any  of  these  may 
be  darkened  by  the  presence  of  organic  matter. 


EXERCISE    A-30. 


TO    SHOW    THE    EFFECT    OF    LIME 
UPON    THE    SOIL. 


Equipment:  Two  tall  bottles  or  cylinders;  a  sample 
of  clay  soil;  a  lump  of  lime. 

Method:  (1)  Make  up  a  small  quantity  of  limewater 
by  dissolving  a  lump  of  lime  in  a  glass  of  water.  Add 
lime  until  no  more  will  dissolve. 

Fill  each  bottle  or  cylinder  with  clear  water  and  add 
to  each  a  tablespoonful  of  very  fine,  dry,  clay  soil.  Into 
one  cylinder  pour  two  tablespoonfuls  of  limewater.  Now 
shake  each  cylinder  for  two  minutes  and  then  allow  the 
contents  to  settle  for  a  short  time.  In  which  sample  are 
the  particles  drawn  together  in  groups  or  crumbs? 

Note  the  time  required  for  the  water  to  become  clear 
in  each  sample  and  record  in  the  following  table: 


Time. 

With  lime 

Without  hme.  . 

(2)  Make  a  mud  ball  of  heavy  clay  about  the  size 
of  a  baseball.  Make  a  second  ball,  mixing  into  the  clay 
two  tablespoonfuls  of  hme,  and,  as  soon  as  both  are  dry, 
crush  them.  Which  is  the  more  easily  broken?  If  a  hard, 
cloddy  soil  is  treated  with  lime  what  will  be  the  effect 
upon  its  working  qualities? 

63 


Fig.  26. — The  Presence  of  these  Weeds  Indicates  that  the  Soil  Needs 
Lune.     Field  sorrel  to  the  right  and  horse-tail  rush  to  the  left. 

64 


TO  SHOW  THE  EFFECT  OF  LIME  UPON  THE  SOIL    65 

Discussion:  The  addition  of  lime  to  a  heavy  clay 
soil  causes  the  very  fine  particles  of  which  it  is  composed 
to  draw  together  into  crumbs  or  granules.  Then  when 
the  soil  dries,  instead  of  being  a  hard,  solid  mass  which 
will  break  up  and  form  hard  clods,  it  is  loose  and  mellow. 
A  similar  effect  is  produced  by  the  addition  of  organic 
matter  in  the  form  of  stable  manure,  or  by  plowing  under 
a  crop  of  clover  or  rye. 


EXERCISE  A-31.     TO  STUDY  THE  NEED  OF  THE  SOIL 

FOR   LIME. 

Equipment;  Blue  litmus  paper;  small  bottle  of  hydro- 
chloric acid. 

Method:  (a)  Dip  the  end  of  one  strip  of  litmus  paper 
into  vinegar  or  hydrochloric  acid,  and  the  end  of  another 


Fig.  27. — A  Small  Outfit  for  Crushing  and  Pulverizing  Limestone  for 

Use  on  Acid  Soils. 


strip  into  lime  water.  What  is  the  result?  After  thor- 
oughly washing  the  hands,  make  a  mud  ball  by  moisten- 
ing some  of  the  soil  to  be  tested,  with  distilled  or  fresh 
rain-water,  and  pressing  it  into  shape.  Break  open  the 
ball,  place  a  fresh  piece  of  the  blue  litmus  between  the  two 

parts  and  press  them  together.     After  four  or  five  minutes 

66 


TO  STUDY  THE  NEED  OF  THE  SOIL  FOR  LIME    67 

examine  the  paper;  if  it  has  turned  pink  there  is  acid 
present  in  the  soil.  The  amount  of  acid  is  roughly  indicated 
by  the  rapidity  of  the  change  and  the  intensity  of  the 
color. 

A  thorough  examination  of  the  soil  requires  that  samples 
of  both  surface  and  subsoil  should  be  tested  at  several 
places  in  the  field. 

(b)  Place  a  small  quantity  of  moist  soil  in  a  saucer, 
add  a  drop  of  vinegar  or  other  acid  and  apply  the  litmus 
paper  test.  Add  to  the  soil  in  the  saucer  a  spoonful  of 
lime  and  after  adding  a  little  water,  mix  thoroughly  and 
allow  to  stand  for  some  time.  Again  test  with  the  litmus 
paper  and  note  the  result.     What  has  become  of  the  acid? 

Discussion:  Acid  cannot  exist  in  the  presence  of  lime. 
The  latter  is  naturally  present  in  some  soils  but  absent 
in  others.  The  presence  of  any  considerable  amount  of 
lime  in  the  soil  can  be  determined  in  the  following  manner. 
Moisten  a  sample  of  the  soil  and  mold  it  into  a  shallow  cup. 
Pour  a  few  drops  of  dilute  hydrochloric  acid  *  into  this  cup 
and,  if  lime  is  present,  bubbles  appear  at  the  surface  of 
the  soil.  If  a  large  amount  of  lime  is  present,  foaming 
will  occur.  Put  a  drop  of  hydrochloric  acid  on  a  piece  of 
limestone. 

As  in  the  case  of  the  test  for  acidity,  the  test  for  lime 
should  be  applied  to  the  subsoil,  since  an  abundance  of 
lime  at  a  depth  of  two  or  three  feet  may  serve  a  very 

*  One  part  of  hydrochloric  acid  to  one  part  of  water.  Care  must 
be  taken  to  prevent  the  strong  acid  from  coming  in  contact  with 
the  skin  or  the  clothing.  In  case  acid  gets  on  the  fingers,  injury  will 
be  prevented  if  the  hand  is  washed  promptly  or  rubbed  with  soil. 


68      FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

useful  purpose.  Soils  that  are  lacking  in  lime  are  usually 
sour  or  acid  and  will  not  produce  a  full  crop  until  lime 
has  been  applied  to  kill  the  acid.  If  a  soil  turns  the  lit- 
mus paper  red  and  refuses  to  grow  good  clover,  it  should  be 
treated  with  a  ton  or  two  of  fine-ground  limestone.  If 
the  soil  bubbles  freely  when  hydrochloric  acid  is  appHed, 
no  lime  is  needed. 


A 


EXERCISE  A-32. 


TO    STUDY    THE    ADAPTABILITY    OF 
SOILS   TO    CROPS. 


Equipment:     Spade  or  soil  auger;  note-book. 

Method:  Make  a  trip  across  several  farms  and  note 
the  kind  of  crops  that  are  being  grown  on  sandy  soils, 
on  clay  loams  and  on  wet  clay  soils. 


Fig.  28. — The  Effect  of  Lime  upon  the  Growth  of  Clover. 

Discussion:  Some  crops  can  be  grown  on  a  great 
variety  of  soils,  while  others  require  a  particular  type  for 
profitable  growth.  Timothy  can  be  grown  successfully  on 
heavy  clay,  clay  loam  or  sandy  loams,  but  it  usually  does 
best  on  the  clays,  while  corn  is  grown  most  profitably  on 
rich  loam  soil..    Irish  potatoes  require  a  loose  rich  loam 

69 


70     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

for  their  best  development,  while  onions  and  celery  are 
grown  almost  exclusively  on  black  soils,  very  rich  in  humus. 
Write  an  account  of  your  observations,  making  note 
of  the  extent  to  which  the  crops  in  your  region  vary  on 
the  different  soils. 


EXERCISE  A-33.  TO  STUDY  THE  PLOW. 

Equipment:  A  breaking  plow;  straight-edge,  or  yard- 
stick. 

Method:  Examine  the  plow  thoroughly  and  answer 
the  following  questions: 


olJboard 
ces 
Landside 


Share' 


Suction 


Fio.  29. — Parts  of   the  Plow.     Note  the  shape  of  landside  and  share 

to  give  suction. 


1.  Name  of  the  plow. 

2.  Name  and  address  of  the  manufacturer. 

3.  Locate  the  following  parts:    mouldboard,  shin,  share, 

point,     beam,     clevis,    landside,    heel,    frog,    and 
coulter. 

4.  By  means  of  the  straightedge  and  a  rule  determine 

the  suction. 

5.  Plow  is  the  plow  adjusted  to  cut  a  wider  furrow 

slice? 

6.  How  is  the  depth  regulated? 

71 


72     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

Discussion:  The  purpose  of  the  plow  is  to  invert  and 
pulverize  the  surface  six  or  eight  inches  of  soil  and  to  turn 
under  weeds  and  other  trash.  The  plow  is  a  three-sided 
wedge,  the  two  plane  sides  of  which  press  on  the  bot- 
tom and  the  landside  of  the  furrow  wliile  the  third  curved 
surface  lifts  and  turns  the  furrow  slice. 

Great  care  should  be  exercised  to  have  the  plow  in  proper 
adjustment,  for  if  improperly  set  the  implement  is  difficult 
to  operate  and  does  inferior  work.  If  possible  make  a  trip 
to  the  field  and  observe  the  operation  of  the  plow. 

Care  must  be  taken  not  to  plow  when  the  soil  is  too 
wet.  If  plowed  too  wet  most  soils  ]:)ecomo  puddled  and 
cloddy  and  may  have  their  productive  capacity  impaired 
for  a  number  of  years. 


EXERCISE  A-34.     TO  STUDY  PLANT  ROOTS  AND  THEIR 
RELATION    TO    SOIL    MANAGEMENT. 

Equipment:     Spade;  yardstick. 

Method:  Dig  down  beside  a  corn  plant  in  a  field, 
and  measure  the  depth  of  the  first  roots,  also  the  depth 
to  the  deepest  roots.  Repeat  this  in  several  places  and 
in  different  kinds  of  soil.  How  deep  may  corn  be  culti- 
vated without  injuring  the  roots? 

In  the  same  manner  find  the  depth  and  lateral  extent 
of  the  roots  of  grasses  and  clovers. 

Of  the  plants  examined,  which  would  tend  to  deepen 
the  soil  and  be  the  most  valuable  in  supplying  humus? 

Discussion:  Roots  which  penetrate  deep  into  the  soil 
open  up  the  subsoil  and  increase  the  feeding  room.  The 
decay  of  roots  adds  humus  and  makes  the  soil  more  pro- 
ductive. 

Plants  are  like  animals  in  that  they  must  have  food 
and  drink  or  they  soon  sicken  and  die.  Animals  can  move 
about  from  place  to  place  and  secure  their  food,  but  plants 
must  get  their  food  and  w^ater  by  sending  their  roots  out 
into  the  soil.  The  tiny  roots  which  spread  out  through 
the  soil  are  busy  all  of  the  time  taking  up  water  from  the 
soil  for  the  use  of  the  stalk  and  leaves  above.  This  water, 
as  it  goes  into  the  plant  through  the  roots,  carries  with 
it  the  plant  food  which  it  has  dissolved  out  of  the  little 
soil  particles.  The  water  that  goes  in  through  the  roots 
passes  out  through  the  leaves  into  the  air  and  leaves  the 
plant  food  behind  to  build  up  the  tissues  of  the  plant. 

If  the  soil  is  hard  and  lumpy,  the  little  roots  cannot 
penetrate   far   into   it,  but   must   feed   near   the   surface. 

73 


74     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 

Stirring  up  the  soil  and  breaking  up  the  clods  brings  the 
water  into  contact  with  more  soil  surface  and  hastens  the 
solution  of  the  plant  food. 


Fig.  30.— The  Root  System  of  a  Mature  Corn  Plant  to  the  Depth 

of  Three  Feet, 


EXERCISE  A-35.     TO  STUDY  THE  ROOTS  OF  LEGUMES. 

Equipment:     Spade;  yardstick. 

Method:  Carefully  dig  up  a  clover  plant  in  the  field, 
noting  the  tiny  nodules  on  the  roots.  Dig  up  other  legumes 
and  observe  their  root  system  and  the  presence  of  nodules. 

These  nodules  are  the  home  of  the  bacteria  which  have 
the  power  of  taking  the  nitrogen  from  the  soil  air  and 
making  it  available  for  the  use  of  the  clover  plant. 

Discussion:  Nitrogen  is  a  very  important  food  for 
plants  and  is  very  expensive  when  purchased  in  fertilizer. 
Only  the  legumes  that  have  the  nodules  on  their  roots  are 
able  to  use  the  free  nitrogen  of  the  soil  air.  The  legumes 
include  the  common  clovers,  alfalfa,  soy  beans,  cow  peas, 
garden  peas  and  many  other  plants,  all  of  which  have  a 
beneficial  effect  upon  the  soil. 

Roots  showing  the  nodules  may  be  preserved  in  cans 
or  wide-mouthed  bottles  by  the  use  of  formalin  *  solution, 
consisting  of  one  tablespoonful  of  formalin  to  each  quart 
of  water. 

Observe  that  the  nodules  on  the  clovers  and  alfalfa 
are  quite  small,  while  those  on  peas  and  soy  beans  are 
much  larger.  In  addition  to  the  nitrogen  which  red  clover 
and  alfalfa  bring  to  the  soil,  they  exercise  a  very  beneficial 
effect  upon  the  physical  condition  by  means  of  their  strong, 
deep  root  system. 

*  Formalin  (40%)  can  be  purchased  at  any  drug  store.  It  is  a 
clear,  colorless  liquid. 

75 


76     FIELD  AND  LABORATORY  STUDIES  OF  SOILS 


Fig.  31. — Nodules  on  an  Alfalfa  Root.      These  nodules  are  the  homes 

of  nitrogen-gathering  bacteria. 


1   1        n         1       > 


>\^  ^ 


TO  STUDY  THE  ROOT^?.  OF  LEGl^dES  /  \       77 


Fig.  32. — Nodules  on  the  Roots  of  Soy  Beans. 


THE  WILEY  TECHNICAL  SERIES 

EDITED    BY 

JOSEPH    M.    JAMESON 


A  serie-"^  of  carefully  adapted  texts  for  usein  technical, 
vocational  and  industrial  schools.  The  subjects  treated 
will  include  Applied  Science;  Household  and  Agricultural 
Chemistry;  Electricity;  Electrical  Power  and  Machinery; 
Applied  Mechanics;-  Drafting  and  Design;  Steam;  Gas 
Engines;  Shop  Practice;  Applied  Mathematics;  Agriculture; 
Household  Science,  etc. 

The  following  texts  are  announced;  others  are  being 
added  rapidly: 

ELECTRICITY 

THE  ELEMENTS  OF  ELECTRICITY;  For  Technical  Students. 
By  W.  H.  TiMBiE,  Head  of  Department  of  AppKed  Science, 
Wentworth  Institute.  xi4-556  pages,  514  by  8.  415  figures. 
Cloth,  $2.00  net. 

THE  ESSENTIALS  OF  ELECTRICITY;  A  Text-book  for  Wire- 
men  and  the  Electrical  Trades.  By  W.  H.  Timbie,  Wentworth 
Institute.  Flexible  covers,  pocket  size,  xiii+271  pages,  5  by  73^. 
224  figures.     Cloth,  $1.25  net. 

CONTINUOUS  AND  ALTERNATING  CURRENT  MACHIN- 
ERY. By  Professor  J.  H.  Morecroft,  Columbia  University. 
1x4-466  pages,  5U  by  8.     288  figures.     Cloth,  $1.75  net. 

CONTINUOUS  AND  ALTERNATING  CURRENT  MACHIN- 
ERY PROBLEMS.  By  W.  T.  Ryan,  E.E.,  Assistant  Professor 
of  Electrical  Engineering,  the  University  of  Minnesota.  40  pages, 
514  by  8.     Cloth,  50  cents  net. 

5M  9/12/16 


ALTERNATING  CURRENT  ELECfTRICITY  AND  ITS  APPLI- 
CATION TO  INDUSTRY.  By  W.  H.  Timbie,  Head  of 
Department  of  Applied  Science,  Wentworth  Institute,  and  H.  H. 
HiGBiE,  Professor  of  Electrical  Engineering,  University  of  Mich- 
igan. First  Course,  x +534  pages,  5!  by  8.  389  figures.  Cloth, 
$2.00  net. 

Second  Course,  ix+729  pages.  5j  by  8.  357  figures.  Cloth 
$3.00  net. 

ELECTRIC  LIGHTING.  By  H.  H.  Higbie,  Professor  of  Electrical 
Engineering,  University  of  Michigan.     {In  preparation.) 

HEAT  AND  HEAT  ENGINEERING 

HEAT;  A  Text-book  for  Technical  and  Industrial  Students.  By 
J.  A.  Randall,  Instructor  in  Mechanics  and  Heat,  Pratt  Institute. 
xiv+331  pages,  5H  by  8.     80  figures.     Cloth,  $1.50  net. 

GAS  POWER.  By  C.  F.  Hirshfeld,  Professor  of  Power  Engineering, 
Sibley  College,  Cornell  University,  and  T.  C.  Ulbricht,  formerly 
Instructor,  Department  of  Power  Engineering,  Cornell  University. 
viii+198pages,  5Mby  8.     60  figures.     Cloth,  $1.25  nef. 

STEAM  POWER.  By  C.  F.  Hirshfeld,  Professor  of  Power  Engi- 
neering, Sibley  College,  Cornell  University,  and  T.  C.  Ulbricht, 
formerly  Instructor,  Department  of  Power  Engineering,  Cornell 
University,     viii+419  pages.     534  by  8,  228  Figures.  Cloth. 

HEAT  AND  LIGHT  IN  THE  HOUSEHOLD.  By  W.  G.  Whitman, 
State  Normal  School,  Salem,  Mass.     {In  preparation.) 

MECHANICS  AND   MATHEMATICS 

ELEMENTARY  PRACTICAL  MECHANICS.  By  J.  M.  Jameson, 
Girard  College,  formerly  of  Pratt  Institute,  xii+321  pages,  5  by 
7M-     212  figures.     Cloth,  $1.50  ncf. 

MATHEMATICS  FOR  MACHINISTS.  By  R.  W.  Burnham, 
Instructor  in  Machine  Work,  Pratt  Institute  Evening  School. 
vii+229  pages,  5  by  7.     175  figures.     Cloth,  $1.25  net. 

PRACTICAL     SHOP     MECHANICS    AND     MATHEMATICS. 

By  James  P.  Johnson,  Sui)crintendcnt  of  the  State  Trade  School, 
Bridgeport,  Conn,  viii+130  pages,  5  by  7.  81  figures.  Cloth, 
$1.00  net. 


ARITHMETIC    FOR    CARPENTERS    AND    BUILDERS.     By 

R.  BuRDETTE  Dale,  Assistant  Professor  in  charge  of  Vocational 
Courses  in  Engineering  and  Correspondence  Instruction,  Iowa  State 
College,     ix+231  pages,  5  by  7.     109  figures.     Cloth,  $1.25  net. 


SHOP   TEXTS 

MACHINE  SHOP  PRACTICE.  By  W.  J.  Kaup,  Special  Repre- 
sentative, Crucible  Steel  Company  of  America,  ix+227  pages, 
5M  by  8.     163  figures.     Cloth,  $1.25  net. 

PATTERN  MAKING.  By  Frederick  W.  Turner  and  Daniel 
G.  Town,  Mechanic  Arts  High  School,  Boston,  v+114  pages, 
5  by  7.     88  figures.     Cloth,  $1.00  net. 

PLAIN  AND  ORNAMENTAL  FORGING.  By  Ernest 
Schwarzkopf.  Instructor  at  Stuyvesant  High  School,  New  York 
City.     {Ready  September,  1916.) 


DRAFTING  AND   DESIGN 

DECORATIVE  DESIGN.      A  Text-Book  of  Practical  Methods. 

By  Joseph  Cummings  Chase,  Instructor  in  Decorative  Design  at 
the  College  of  the  City  of  New  York  and  at  Cooper  Union  Woman's 
Art  School,  vi+73  pages.  8  by  10^-  340  figures.  Cloth, 
$1.50  net. 

AGRICULTURAL  DRAFTING.  By  Charles  B.  Howe,  M.E. 
viii+63  pages,  8  by  10^.    45  figures,  26  plates.     Cloth,  $1.25  net. 

ARCHITECTURAL  DRAFTING.  By  A.  B.  GreExNberg,  Stuy- 
vesant Technical  High  School,  New  York,  and  Charles  B.  Howe, 
Bush  wick  Evening  High  School,  Brooklyn.  viii  +  110  pages, 
8  by  10%.     53  figures,  12  plates.    Cloth,  $1.50  net. 

MECHANICAL  DRAFTING.       By    Charles    B.    Howe,    M.E., 
.  ■     Bushwick  Evening  High  School,  Brooklyn.      {In  preparation.) 

ENGINEERING  DRAFTING.  By  Charles  B.  Howe,  M.E., 
Bushwick  Evening  High  School,  Brooklyn,  and  Samuel  J.  Berard, 
Sheffield  Scientific  School,  Yale  University.     {In  preparation.) 

DRAWING  FOR  BUILDERS.  By  R.  Burdette  Dale,  Director 
of  Vocational  Course,  Iowa  State  College.  {In  press.  Ready 
September,  1916.) 


AGRICULTURE  AND  HORTICULTURE 

FIELD  AND  LABORATORY  STUDIES  OF  SOILS.  By  Pro- 
fessor A.  G.  McCall,  Ohio  State  University,  viii+77  pages, 
5  by  7.     32  figures.     Cloth,  60  cents  net. 

FIELD  AND  LABORATORY  STUDIES  OF  CROPS.  By  Pro- 
fessor A.  G.  McCall,  Ohio  State  University,     viii+133  pages, 

5  by  7.     54  figures.     Cloth,  85  cents  net. 

SOILS.     By  Professor  A.  G.  McCall,   Ohio  State  University.     {In 

-preparation.) 

MARKET  GARDENING.     By  Professor  F.  L.  Yeaw,  Oasis  Farm 

6  Orchard  Company,  Roswell,  New  Mexico.  Formerly  Professor 
of  Market  Gardening,  Massachusetts  Agricultural  College,  vi-f 
120  pages,  5  by  7.     36  figures.     Cloth,  75  cents  net, 

AGRICULTURAL  CHEMISTRY.  By  Professor  T.  E.  Keitt, 
Clemson  Agricultural  College.     {Ready  November,  1916.) 

STUDIES  OF  TREES.  By  J.  J.  Levison,  Forester,  Park  Depart- 
ment, Brooklyn,  N.  Y.  x+253  pages,  534  by  8.  156  half-tone 
illustrations.     Cloth,  $1.60  net. 

AGRICULTURAL    DRAFTING.      By  Charles  B.  Howe,  M.E. 

46  pages,  8  by  10^-     45  figures,  22  plates.     Cloth,  $1.25  net. 

PRACTICAL  ENTOMOLOGY  FOR  SCHOOLS.  By  Dean  E.  D. 
Sanderson  and  Professor  L.  M.  Peairs,  West  Virginia  Univer- 
sity.    {Ready  October^  1916.) 


BIOLOGY 

LABORATORY    MANUAL   IN   GENERAL   MICROBIOLOGY. 

Prepared  by  the  Laboratory  of  Bacteriology,  Hygiene  and  Path- 
ology. Michigan  Agricultural  College.  xvi+41S  pages,  5^  by  8. 
73  figures.     Several  tables  and  charts.     Cloth,  $2.50  net. 


THE    LOOSE   LEAE  LABORATORY  MANUAL 


A  series  of  carefully  selected  exercises  to  accompany  the  texts 
of  the  Series,  covering  every  subject  in  which  laboratory  or  field 
work  may  be  given.  Each  exercise  is  complete  in  itself,  and  is 
printed  separately.     8  by  10^. 


Important  Notice 
WILEY  LOOSELEAF  MANUALS 

The  sale  of  separate  sheets  of  the  Laboratory  Manuals  of  the  Wiley 
Technical  Series  has  been  discontinued.  These  Manuals  will,  here- 
after, be  sold  only  as  a  complete  book  with  removal  leaves.  Descriptive 
literature  will  be  sent  on  request. 

CHEMISTRY 

Exercises  in  General  Chemistry.  By  Charles  M.  Allen, 
Head  of  Department  of  Chemistry,  Pratt  Institute.  An 
introductory  course  in  Applied  Chemistry,  covering  a  year's 
laboratory  work  on  the  acid-forming  and  metallic  elements  and 
compounds.  62  pages,  8  by  103^.  61  exercises. 
Complete  in  paper  cover.     Removal  leaves.     $1.00  net. 

Quantitative  Chemical  Analysis.  By  Charles  M.  Allen,  Head 
of  Department  of  Chemistry,  Pratt  Institute.  12  pamphlets. 
8 by  103/2-  Complete  in  paper  cover.    Removal  leaves.    $1.00  nc^. 

Qualitative  Chemical  Analysis.  By  C.  E.  Bivins,  Instructor  in 
Qualitative  Analysis,  Pratt  Institute,  11  pamphlets,  supple- 
mented by  Work  Sheets  by  which  the  student  is  taught  equa- 
tions and  chemical  processes.  Complete  with  work  sheets  in 
paper  cover.     Removal  leaves.     $1.25  net. 

Technical  Chemical  Analysis.  By  R.  H.  H.  Aungst,  Instructor 
in  Technical  Chemistry,  Pratt  Institute.  19  pamphlets.  8  by 
103/^.      Complete.     Removal  leaves.    85  cents  net. 

Exercises  in  Industrial  Chemistry.  By  Dr.  Allen  Rogers, 
Instructor  in  Qualitative  Analysis,  Pratt  Institute.  (In  prep- 
aration.) 


THE  LOOSE  ].EAF  LABORATORY  MANUAL— Con^ 

MECHANICS  AND  HEAT 

Exercises  in  Mechanics.  By  J.  M.  Jameson,  Girard  College; 
Formerly  of  Pratt  Institute.  52  exercises.  Complete  in  paper 
cover.     Removal  leaves.     85  cents  net. 

Exercises  for  the  Applied  Mechanics  Laboratory.  Steam; 
Strength  of  Materials;  Gas  Engines;  and  Hydraulics.  By 
J.  P.  KoTTCAMP,  M.E.,  Instructor  in  Steam  and  Strength  of 
Materials,  Pratt  Institute.  8  by  10^^.  58  exercises,  with 
numerous  cuts  and  tables.  Complete  in  paper  cover.  Ren[>oval 
leaves.    $1  net. 

ELECTRICITY 

Exercises  in  Heat.  By  J.  A.  Randall,  Instructor  in  Mechanics 
and  Heat,  Pratt  Institute.  13  exercises,  with  numerous  cuts 
and  diagrams.  8  by  lOJ/^.  Complete  in  paper  cover.  Removal 
leaves.    26  cents  net. 

Exercises  in  Electricity,  A.  C.  and  D.  C.     By  W.  H.  Timbie, 

Head  of  Department  of  Applied  Science,  Wentworth  Institute. 
49  Exercises.     Complete  in  paper  cover,  85  cents  net. 

Elementary  Electrical  Testing.  By  Professor  V.  Karapetoff, 
Cornell  University,  Ithaca,  N.  Y.  25  exercises.  Complete 
in  paper  cover.     Removal  leaves.    50  cents  net. 

Electrical  Measurements  in  Testing.  {Direct  and  Alternating 
Current.)  By  Ciiestek  L.  Dawes,  Instructor  in  Electrical  En- 
gineering, Harvard  University.  In  charge  of  Industrial  Elec- 
tricity, Franklin  Union,  Boston.  39  Exercises.  Complete  in 
paper  cover.     Removal  leaves.     75  cents  net. 

AGRICULTURE   AND  HOirriCULTURE 

Studies  of  Trees:  Their  Diseases  and  Care.  By  J.  J.  Levison, 
M.F.,  Lecturer  on  Ornamental  and  Shade  Trees,  Yale  University 
Forest  School,  Forester  to  the  Department  of  Parks,  Brooklyn, 
N.  Y.  20  pamphlets,  8  by  103^.  $1.00  net.  A  cloth  binder  for 
above  sold  separately.     50  cents  nc^    . 


THE  LOOSE  LEAF  LABORATORY  MANUAL— Con«. 


Exercises  in  Farm  Dairying.  By  Professor  C.  Larsen,  De- 
partment of  Dairy  Husbandry,  South  Dakota  State  College. 
Loose  leaf.  8  by  10|.  69  Exercises.  Complete.  Removal 
leaves.     $1.00  net. 

Exercises  in  AgricxilturaJ  Chemistry.  By  Professor  T.  E.  Keitt, 
Clemson  Agricultural  College.     {In  preparation.) 

DRAWING 

AGRICULTURAL  DRAFTING  PROBLEMS.  By  Charles  B. 
Howe,  M.E.  A  Manual  for  Students  of  Agriculture  to  Sup- 
plement the  Text  in  Agricultural  Drafting.  26  plates.  8  by 
103^.     In  paper  cover.     Removal  leaves.     50  cents  7iet. 

THE  ORDERS  OF  ARCHITECTURE.  By  A.  Benton  Greenberg. 
A  Manual  for  Students  of  Architecture  to  Supplement  the 
Text  in  Architectural  Drafting.  20  plates.  8  by  103^.  In  paper 
cover.      Removal  leaves.     50  cents  net. 


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